MTN to refund my money

I have a problem with Mtn and its not even being resolved instead they drop off the phone,what happened is that Mtn offered me home router I accept but within 3 days I returned it back because I didn’t need it because I have a router that I curry everywhere.so from November they been deducting from my account been trying to solve this from last year November but no lucky they drop their phones but now okay now they did cancel the contact last month but now they blocked my phone telling me I owe R2000 its the cancellation fee when I asked them it’s fine refund my mine that you guyz been deducting because I never use the router neither to open it no one is helping me they drop me or say will transfer you to managers then few minutes they end the Call I am so disappointed with them I can’t to anything am not working am expecting calls from the companies that I app**** to please help me MTN is a *****