TELKOM WITHHOLDING MONEY DUE TO ME FOR 3 MONTHS

I closed my account at the end of March / early April of 2020 and I am still waiting for them to credit my account. They never answer costing money on airtime and when they do answer they give me a run around asking for reference numbers, then telling me I need to supply my banking information (which is confidential) in order for me to get my money that's owed to me! They do not take this seriously and I need to speak a senior manager or director cause I need my money!!! Its been 2 - 3 months that I am waiting & they making feel like I owe them money yet it is money that is due to me!