****** by cell c

I went to cell c to inquire if I could get a combo deal in Menly Pretoria on February as MTN was offering one. Cell C sales lady told me that I can get any two phones of my choice as it can be converted to a combo deal because I mentioned that I am willing to spend R500 monthly. We then proceeded with the transaction, however, she had only one phone on the stock. I took one phone that day and signed for that one then two days later I came to collect another phone and I was told to sign for the second phone for evidence that I have collected the phone. However, I realised that the lady made me sign for two separate contracts for R500 each. I complained and I was got ignored and did not get helped. I tried calling customer care but no assistance. Now, I am being threatened to be blacklisted because I am not satisfied with the transaction. Can somebody please advice