Standard Bank selling my debt to third parties?

I received a sms from Standard Bank to increase my credit card limit. To date, I have still not received any reply. Imagine my surprise when I called the credit card division yesterday to learn this process is done by a third party. Imagine my shock when I asked to increase my credit card limit with R20 000 less than what was offered via sms and it was actually declined. The internal team says they cannot assist me. But a third party supplier can give me R20k more than I asked for? Who gave you the right to sell my debt to a third party? And how can you possibly decline my application internally but some third party offers me R20k more than my own bank, under the auspice of being my own bank? I STILL HAVEN'T EVEN HAD A REPLY TO THE ORIGINAL COMPLAINT I LOGGED. I am so sick of your total lack of service and bizarre policies and procedures. I am not continuing my 12 year relationship with Standard Bank any longer. This for a person who has an impeccable credit record and deserves a lot better than the shoddy service I have received to date.