Appalling service at MTN!!!!!

I logged a query with MTN (Ref:***) on the 7th January after they tried to deduct +R900 from my account instead of R169 till today I have not been assisted. Then it increased to R1173.42 and now it's R1761.41, they blocked my phone from doing anything, I follow up everyday and I have asked if I can pay my monthly subscription so they can open my phone while they investigating and they declined. For almost 2 months I have no phone, when I go to their branch they are always offline or can't help over the weekend. Please help I don't know what to do now 😞