"Available funds"

Three weeks ago I ordered a new card for my blue bean credit card. I collected the card on 28th October and also asked the lady what the available funds was and was told I can check at the atm. The atm showed that my available funds was R32000 so obviously a lot of things went through my head. Also the blue bean card has been changed to standard bank gold credit card. I used from that money and on the 7th of November received an sms to say that if I continued using my card it will be considered as *****. I phoned the number from the sms and spoke to different people. I was also asked by Nikita why I used my available funds as it was not available to me! At the end of the day I was forced to make a payment plan. Obviously I was thinking my instalments would increase per month but was told it is due immediately! I also asked them then to increase my limit and was told they can't as I went over my limit. What I want to know now is because they did put me on a payment plan does this mean it will affect my credit record and I will be charged more. Is there any legal advice I can get on this matter?