Virgin taking money as they please

Joined service and 1st debit order was correct and the 2nd & 3rd month they increased debit order without my knowledge and approval. Virgin states that we are not allowed to break contract but they do by changing terms and debit orders as they please. They said they will re-imbursed but no one gets back to me. The consultant (Rodney) at Virgin active near Makro Centurion also gave very bad service and attitude and never got back to us even when we left messages. He eventually called me back with a very bad attitude as if he was the victim. Hereby I want full re-imbur*****t (R1700) and contract be cancelled. We made numorous phone calls but no one really assisted us in this regard. The manager Albert Terblance is also not available after 2 calls were made. We are struggling with Virgin since 2 June to solve this issue but again no one gets back to us.