Refund

I'm so disappointed with MTN customer service both online and branch. I recently took a contact with MTN for wifi on the 08 July 2024 upon taking this contact the service provider informed that I will be paying for tge remaining day ls of July as well as August indeed I did. On the 15 July 2024 I was debited against two time this, I reported this matter and only got a refund for one payment. It's over a month trying to get a refund or even an explanation to what is happening but with no luck, they have been opening and closing my case till this day. What mtn did now is to disconnect my wifi, when I'm enquiring about this they say I am owing August fee and what I paid for was to rent the wifi router, I told them this was informed initially when I told this contact but was told I'm paying for August and also on the advert of this offer it's written that the router is free. Customer service agents have been transferred to multiple agents, putting me on hold without any resolutions, the branch told they don't assist anyone who didn't buy on they branch. I don't know what steps to take regarding this matter.