Big corporates bulling

I received a marketing message form Std Bank to apply for a credit card limit increase. As I hold a suite of products with Std Bank i.e. 2 home loan accounts, credit card and chq account for the past 19 years. Then I app**** for the credit card limit increase which was declined due to a R600 payment dispute that I occurred more than 5 years ago with a MTN. Irrespective of my motivation and my unblemished credit record with Std Bank for the past 19 years. Std Bank is forcing me to payoff the dispute with MTN before I can get a credit card limit increase. Very short sighted Bank which is not willing to assist its customers, unless they derive more value siding with MTN. I will not be bul**** or sanctioned to submission by big corporates.