Unfair business practice

I changed my banking details before debit date,informed the company on time.Even paid earlier since I got paid,then informed them I have already made payment for that month.They assured me the debit won't go through...boom the debit went through.I contacted them,then they promised to refund me in 7 days which was acceptable.7 days came and went no refund,then I contacted them,they claimed to have refunded me on the old closed bank account.I went to request the bank statement which proved there was no refund.They claimed they will investigate,that was in March.April I made a follow up and was referred to their Attorney since I reported the issue to Ombudsman after several attempts to get my money back.The attorney requested the bank statement which I sent,promised to revert back to me same day,never did till this day.Then since my contract was to come to an end I requested they cancell it,which they sent an email that it was cancelled.Then boom again May 31,they debit my account.I contact them,they say nothing as such happened,then I sent my statement as proof.Next reply was...since the matter is with Ombudsman,contact them for your query.