Six requests for answer on owed data as per new contract ignored over 3 months

We bought Samsung Tab E on contract and it was suppose to come with 10 gig for three months but we never received anything. We've been making queries since August and have several reference numbers but nobody ever calls back and no one has been able to assist. I've sent requested copies of contracts and have waited patiently over three months. Nothing. Truly horrible experience. Walking away from MTN forever