What happened to my packs?

I was driving my cousins mamba rusty. I was using my 7 cell packs for it. I have been driving it with these but today I head a puff sound and I didnt know what it was, so I brought it in and the shrink rap popped! I spent all of my money on these packs! $150 I hope I can get a new set. :( I just wish I could get a full run without somthing going wrong.