Billed for no product

I am an Mweb subscriber since 2020 my account number :***7, I had no problem since then up until I ordered mifi router. They delivered TP link router and moderm , I saw the packaging and I immediately log a return because it was a big parcel comparef to a little one I odered, after weeks of waiting for them to come collect they eventually collected it. My problem is that I am being billed on that product even though I never even opened it and when I call them no one seems to be knowledgeable about their product they keep on transferring my call to different departments with no tangible information. No one seems to know how I get the billing even when I log a query online no one attends to queries and they are never resolved, even worse when I make a call, I’ll be holding for 45mins without any information. The worst part they delivered a wifi extender to my house and its no longer picking up power when plugged in when I enquire they don evennhave it in their record, like they do not have it, I’m even thinking of delinking and find a new service provider because I’ve been fighting this since April. I don’t know how many statements I recived in one July with no proper explanation, I reversed a debit order of 5.5K which I dobn’t know where it comes from….. Mweb is not good ISP rather opt for ther providers