can a debit collection ageny garnish my bank account with out proof that i even owe this debit and take more than what was said to be owed.

in 2012 I received a letter from a cdebit collection saying I owed money so I asked or validation of debit, instead I received a summons to go to court. they bullied my wife into making payments while still never proving we owed this debit. we payments on time sometimes making double payments. we paid a few days late on one payment and they refused to take it and said there's nothing I can do about it. when I asked again for proof of this debit they said its to late to bad. I didn't hear from them until I received a letter in 2013 with a settlement which was more then what I originally owed. i called to see why it was so much no had an answer for me and at one point i was told its "behind the scenes costs". i didn't here from them again until Feb. 10th 2014 when they froze my account. i called them and was told i owed 1500 which was less then the settlement letter back in 2013 but then took over 1800 from my account still with no proof that we owe this debit. what are my rights.