MTN Banking Finance Bad Service

I made a payment on the 2nd January 2021, my contract phone was then blocked, i then called and i was told my account is blocked due to missed payment. 22nd January i sent an email with all necessary proof of payment and various consultants has also sent in emails to banking finance but there has been no response or the matter being resolved instead i have been debited the amount, i paid with their MTN and they sent an email confirming payment but now they say i did not pay and not willing to even do their job