Bad service from management.

I bought couches worth R27000, I paid R R11800.00 as a deposit and I was promised cashback of R2000 but only received a R1000. I called to find out what was happening they advised to fixed the problem but nothing was done. I am the one who has to do all kinds of follow-up, I recently called the general manager and introduced myself to her but the call was dropped. I called three time she continued rejecting the call. The service is extremely bad, I am very disappointed.