Refund me and sort my account

Mtn has doubled bill me each and everytime since January 2021. In April i got a call advisig that they will refund me and to date no refund. I got a call in May advising 1 of the numbers on the account is eligible for an upgrade and the upgrade was done. Today the 1 number that was upgraded is double billed and the call centre says it was an early upgrade. When asked to speak to a Manager they advise they cant do a transfer.

I need my account to be urgently sorted out and my refund from previous months and this month to be done.

If not i will involve the ombudsman and attorneys to issue a letter to MTN.