Mtn and Mondo, incompetence

I am really dissapointed at how mtn way of operating. I was contacted by Mondo via telephone regarding my contract upgrade that was due and the lady assisting me informed me of a good offer. Before taking the offer I explained to the lady that I also need a router to come with the deal and enquired whether I can use my number on two sims ( which is the one that will be in the router and cellphone). The lady informed me that I could. The item was delivered and to my surprise when I inserted the sim in the router, I lost the signal on the isim on my phone. A day after delivery which falls within the cooling off period, I went to the Mtn store to cancel the contraft as it was not what I wanted. They said that they do not effect cancellations instore and that I would have to contact the cancellations department. I have been paying for the past 2 months for an unused router. I lodged a complaint around the 9 November 2020 till date the contract is active. Mondo is an ineffecient company that did not answer calls and only assisted when I threatened to go on hello peter to expose them. Mtn at this point is of no assistance as their cancellations department does not answer and as the client you are on hold for hours on end. This is so frustrating. They credited my account again, yet I cancelled the contract with Mondo. I need this whole mess to be sorted out and the deduction towards the router I am not in possession of nor in use of be refunded to me.