MTN uncapped flte very unhappy

Good day I need help

I did an online application for uncapped mtn internet for R499 per month. No where on the application was there specified to check coverage at my address. I entered all my details and a week later the router arrived at my workplace. I went home to check device and it was not working so I contacted MTN via facebook and calling the customer care number. The operators told me that there is no coverage in my area for the flte router. My question is if you do an online application the sales person dispatching this device should have checked that there is no coverage before sending this device.

I returned the router before 7 day cooling off period without being able to use the device. MTN now tells me I have to pay a cancelation fee that I am not happy about. I have no contract signed with them nor did I use the device and is very unhappy about this. The cancelation department just says there is nothing they can do about it. I have always used MTN and very unhappy with their customer service. I do not give MTN consent to debit my account. I have signed no paperwork for anything I need assistance urgently