MTN WiFi router contract

I had a home router contract which is a month to month contract with mtn an I cancelled it on February they decided not to cancel the contract an they keep on deducting money from my account because they hire inexperienced personnel to do the work an nw I'm paying for a router that I'm not using that is in store at MTN makhado Louis trichard but I'm still paying today they have deducted R2300 from my account and it's not reversible hello peter please can you help me with this matter because MTN is robbing people of this country,when I called to cancel the sales consultant told me that I must go to the nearest store cause they cannot help me on the line ,I when to the store but even today I'm still stack with deduction on my account from MTN please help thank you.