fastcash- 500.com they didnt let me kno that my third payment didnt go thru and added all types of fee .a $500 loan went to $1250 Internet, Internet

I received a loan from fastcash 500 for 500 dollars .somehow it came to being 900 I had to pay back ., no problem I needed the $ ..an emergency came up I needed another $500 loan. I made 2 $150 payments, I checked status that was said to be initial payments , I still owed $650..ok the loan did come in handy , so I can't complain ..when it was time for my 4th payment I received a call that I'm 2 payments behind ..I now owe $800.. I asked the rep why wasn't I notified imeadiately that my payment didnt go thru so I could have corrected it instantly..the rep stated ..oh somebody should have called you or emailed you .I see that they didn't , and he can't change the fees.. I called my bank they told me the payment was sent to fast500 and they sent it back ..I'm wondering are they lying to collect more intrest from me .. a $500 loan coated me $1150..they ripped me off real good ..I will never use them again . I hope we can get some kind of class action law suit going against them