MTN CONTRACT

I went to MTN store in Pmb Liberty Mall to cancell my expired contract, only to find that they don't do cancelations in store, very strange cos when I took a contract I did it at the very same store. My worry is that I, ve been trying to call the number for cancelation since the beginning of November but couldn't get through. It rings till my b3 finishes. Can anyone from mtn call me!!!!! Instead they tell me about black Friday deals and said they will charge me if I cancell now cos my contract expired on Nov 25 not considering that I failed to get through via phone.