Faulty Router

I have been contacting Mtn for 3months, for selling me a router that does not work, the contact center said to take it to Mtn stores, the stores cannot take it in because I never received a contract, the router was delivered to me I only received a Tax Invoice, customer service really sucks to think I have 3 contracts with them. Never had a problem till now Just need the Router contract canceled and they take it back,no longer interested in MTN