TV no yet repaired

I bought a bought hi sense 49in at carnival mall on the 4 September 2017 and it's not working. I returned it to the store on the 03 April 2018 and I was assisted by k sekonya In customer service. I went to store spoke to manager and was told they are waiting for authisation for credit. They don't bother to call me unless I call them I called again spoke to zandi and Calvin no respond yet. On the 6 and 8 of may I was promised that they will come back to me no one is calling me. I bought the tv as cash sale. Pls help