Maybe you should be compensated for the first bet you made that was unable to be 'undone' due to the button not working.  Asking them to return the entire deposit, and also the next 5 deposits you dusted off is ludicrous.

When you made those next 5 deposits, did you really believe they would just give you your money back if you lost since the 'undo bet' button wasn't working?  
Any casino allowing themselves to get free rolled like this would go broke very quickly.