Pay back the money!

ADT has really terrible accounts administration. They billed me more than my contract amount for months. I complained about this only for them to correct the deduction but NOT refund all the other ****** money as per my request. I've made several complaints about incorrect billing and unexplained random debit orders since that incident and told them to no longer debit my account. They not only debited my account after that instruction but debited more than my contract amount AGAIN. I am beyond disappointed with ADT. Their accounts and complaints departments are terrible. Not feeling like a "valued customer".