Very bad service and offers they said they will give is not true

I was called by a consultant and they wane to give me R15000 on a credit card. I did agree but 4 days before i got the credit card i login in to the app and my credit was only R700. When i called them they said that the offerd not valid anymore for R15000. I then ask them to close the account as R700 is not going to help me. They did transferd me to deff dept and they said they will come back to me but they did not. I called them more then 4 times to close the account and do have ref no for it but still nothing. Now i got an sms that say i must pay them and i did not even used the card as its still closed and they wane take legal action if i dont pay them but i did not use ths account at all.