Credit card Limit Increase

I received a call from an African bank consultant called Primrose who offered to check if I qualify for a loan. I allowed her and confirmed my details. She then told me I don't qualify for the consolidation loan however, I do qualify for a Credit Card Limit Increase from R4000 to R20000. I took my time from work and went to the nearest branch to finalise the offer as per their sms. I was assisted by a consultant called Molebogeng. I gave her my bank statement, salary advice and everything relevant document she needed. she showed me on the system that I had qualified for a loan of R34 000 but we agreed that I wouldn't take it as I already have a loan with them. So we confirmed the credit card limit increase. The next day I received a call from Molebogeng saying they need a copy of my marriage certificate. I forwarded it. Ten days later she called and told me my application was declined. when I asked reasons, she told me there are none. Why did she take so long to tell me that when the system showed I qualified and signed the contract? She further upgraded my card from blue to gold, why? I no longer want reasons, I want my credit increased. I didn't call them, they called me.