RE: keldeo ex blastoise deck help
I currently run this deck very similar to yours and I see a few things as too why the deck seems to be having "bad luck".
First Supporters... 3 Colress is too many at most run 2, I actually do not run any. 3 skyla is okay that is your choice and preference though. I run 2 N and 4 Cheren/Bianca and I would reccomend something more that way. I also run just 3 Juniper but that could go either way. So with those changes here is what I reccomend. I will give you options to how many of each but keep 13 supporters as how many. What I currently run will be in (Parenthesis).
3-4 Juniper (4)
3-4 Cheren/Bianca (4)
2-3 Skyla (2)
1-3 N (2)
0-2 Colress (0)
0-1 Cilan (1)
Next some of the items are a little off or uneeded. First Random Reciever is not needed when you run 13 supporters, if you are worried still just run another supporter.
-2 Random Reciever
(maybe +1 more Supporter)
I would run 2 Eviolite to help Keldeo Tank.
+2 Evioite
Super Scoop Up in perfect situation is amazing in this deck but in a scramble the card is junk. And it relies completely upon a single flip of the coin, which can be devasting if tails. I prefer is simple alternative, Max Potion. I am not sure how other people view it in this deck but with 4 Energy Retrieval it is no big deal for keldeo. I currently run 1 max potion and might make it two soon.
-3 Super Scoop Up
+1 Max Potion
That is my opinion, in which I think you should test.
Tool Scrapper is needed when you face Garbotoxin decks. So you can keep rushing in.
+1 Tool Scrapper
Then for energies. I run 2 DCE for mewtwo and early attacks with Keldeo, this you should test as well. MAybe jsut run 1? That is your choice.
The deck looks amazing though. Just test different stuff to find the way you like it the most. Most of what I said is major in my opinion talk, because I do not see alot to change. But the Supporter changes I said, should make a big difference for this deck. Hope I Helped!