I had contract with MTN for data, my data was vanishing the very same day the put data when I called in no one couldn’t answer, so I opted to terminate my contract early, this happened in May

I had contract with MTN for data, my data was vanishing the very same day the put data when I called in no one couldn’t answer, so I opted to terminate my contract early, this happened in May. I received an email of the amount I was supposed to pay which I paid, I never got any response, this month (July) they deducted money from my account, when I called they told me the contract is still active it was never terminated so they gave me an another amount to pay, who’s liable to pay for that amount because I already paid the amount they gave me. Customer service is the worst, I emailed them last week, still waiting for the their response even now