Debit and refund query

Iam utterly dissaponited with cellc customer service and they urgency to assist a client. in December I made a payment from the cell c app for my cell phone contract and then they still debit my account which failed and then I got charged bank charges for not paying but clearly I paid account. I have contacted cellc on the 5/01/2022 and uptil now I still did receive any feedback inregards to this query not a phone call from any of the agents.

Everytime I call this they say the matter is still under investigation but when I asked them how long does a refund matter take they say around 3 business working days it's over 20 days with no feedback. Today I called in and spoke to one of the agents to see if there's is any feedback for me but still nothing all he said was the matter of was under investigation. I asked to speak to the manager he tells me that there is no manager avail and they will call me back. I don't recommend any one to take any contracts with cellc because there service delivery is absolutely ****. Worst customer experince ever. And now end of this month they are going to debit me for 2 amounts when I was donly supposed to pay one and then even charged me 70 rand extra and when I asked why they Said becusse I missed a payment in October but I clearly paid my account in October. Absolutely disgusted