TELKOM MOBILE BAD SERVICE

I have an account with Telkom, that they debit every month. As from December 2022 they deduct the wrong amount then they cut my service and when I query this, they say I am over my credit limit, never knew they had a credit limit and why did Telkom then approve and upgraded my phones? I only have 1 week a month that I could use my phone the rest of the month my phone is off needless to say I pay plus minus R2500 on an account that I only use for a WEEK... I went to Greenstone Telkom and phoned the call centre so many times a month and next month we back to the same problem.