Ah, a good ol' bounce/discard deck. I had a deck like this that I played not too long ago. Unfortunately, I never quite made it work the way I wanted to, but I think I learned some things from that effort, and it looks like you've already got a good start - except that your e-mail only shows 54 cards! We'll take care of that, too.

It took me quite a while to figure out just why my deck didn't work well, and it appears that yours would probably have the same problem.

Your two key cards, Megrim and Warped Devotion, are what I call "do nothing" cards. That's not because they are bad cards, but because they do nothing on their own. Megrim is useless if your opponent isn't discarding. Warped Devotion is useless if they aren't returning things to their hands. So basically, you are likely spending 2 turns and 6 mana on cards that have no immediate impact on the game, while your opponent is busy dropping creatures or otherwise trying to take you down. This is a definite hurdle to overcome - but I think we can do it.

What I just described to you is often called a "tempo" problem. Your opponent is setting up his offense against you more quickly and effectively than you're getting yours going. To make up for this, one of the best tempo fixing cards in the game is Remand. I would suggest adding a playset of these to your deck, bringing your total up to 58 cards. Remand will slow down your opponent by a turn and replace itself in your hand with another card.

Along the theme of drawing cards, I think the Spellbombs from Mirrodin would be a good fit for this deck. Aether Spellbomb can bounce a creature, or if they don't have one to bounce, you can essentially cycle it for two mana. The Necrogen Spellbomb would be a good fit too, because if you can't get Warped Devotion going, then you have very little discard. Even if you don't have Megrim, making your opponent discard early is a good way to slow them down until you can get your combo going. The Spellbombs make for good first turn plays, and the Necrogen Spellbomb is rare instant speed discard, so once someone is out of cards in hand, you can make someone discard during their draw step, so they don't have a chance to play non-instant spells. Three of each of these would put your total to 64.

One more thing - Your deck only has 5 cards that deal damage right
now: Megrim and Breathstealer's Crypt. I like both of those choices, but you need more ways to deal damage. If your opponent can manage to keep his hand empty, you'll never get Megrim to do any damage! In that case. the Rack would be a great fit. With the added discard the Necrogen Spellbomb brings, your opponent is even more likely to be low on cards in hand. This will cause the problem for your opponent of whether to keep playing cards and take damage from The Rack, or to slow down their progress by keeping cards in hand so you can make them discard! Four copies of The Rack bring us up to 68.

So, what to drop? Well, we just added some more bounce, so I think you can probably drop Echoing Truth, since you're probably not going to get to bounce more than one thing very often with those. That puts us at 64. Looking through the rest of your deck, I really like Noetic Scales, so it will stay. Perplex, though normally a subpar card, fits in very well with this deck, especially with the transmute ability that can get either Megrim or Warped Devotion. Overburden, however, is another "do nothing" card, and bouncing their land if they play a creature just isn't going to slow them down enough in most cases. I think you can drop those. The other drop I would suggest is Evacuation. With all your other bounce, opponents aren't normally going to have many creatures out, and Evacuation often will turn into a 5 mana Unsummon. This takes us to 58 cards.

I almost forgot - you need an answer for creatures with CIP abilities.
What you need is some basic creature kill. There are countless cards in black that will take care of that, but what strikes me as the best choice for this deck is Mutilate. Most creatures with good CIP abilities will die to it, it takes down untargetable creatures and indestructible creatures, and it can be your board clearer since we dropped Evacuation. 2 of these should do the job. If you can't get Mutilate, Hideous Laughter or Infest would be reasonable substitutes.

Oh, and I'm a little concerned that 20 lands might not be enough.
Let's go ahead and drop the single copy of Dismal Failure and replace it with another Swamp.

Let's see if we've covered all your issues.

Issue #1: "i dont get the warped devotion out i die fast"
Hopefully the added card draw and tempo advantage from Remand and the Spellbombs will help this.

Issue #2: "my stall bounce runs out"
Again, the added card draw should speed you up enough so your bounce won't have to stall as long. Also, the Mutilates would take care of a few creatures that they wouldn't be able to play.

Issue #3: "a 0/x creature that cant be target of spells or abilities and can deal damage in some way could you please tell me it would destroy this deck badly"
I don't know of anything that fits this description, but if there is, Hopefully you can get a Mutilate to take it out.

Issue #4: "creature with come in to play effects are hard to deal with"
Once again, Mutilate should help there. You might even find a place for some other creature kill such as Last Gasp or Sudden Death if you continue having problems there.

After all that, if I was playing this deck, my deck list would be something like this:

9 Swamp
12 Island

21 lands

4 Remand
4 Megrim
4 Recoil
4 Warped Devotion
2 Noetic Scales
4 Perplex
1 Breathstealer's Crypt
4 Boomerang
3 Necrogen Spellbomb
3 Aether Spellbomb
4 The Rack
2 Mutilate

60 cards

As I'll try to say just about every time I fix a deck, this is not a perfect fix. Don't expect to copy this list exactly and win every time. Use these suggestions and see if they help - I think they should. Have fun playing this deck and keep tweaking it as you get ideas.

- mattedesa