Unauthorised Credit reduction

On Wednesday November 25, 2015 i received an SMS stated that my credit card limit has been systematically been adjusted. There was no reason as to why it had been or who authorized this. i called the credit card division and spoke to Zandile Siboza (Agent) to which she advised that i had been selected by card division to participate in an OFFER. An offer to my understanding means i can refuse. she couldnt help me and then placed me on hold for about 5mins (which is unacceptable) I then spoke to Ebrahim Abdoolah (Supervisor) who still told me that he cant help me as they sent me notice prior to the reduction. He states that on their system, the sms was sent out 24/11/2015 at 1 o clock prior to the reduction to which i have not received on that time specified and to which was not in a timeous manner.i have been given conflicting information by FNB call centre employees. And i am still waiting for a manager Ronald Smith to call me to which he is busy!!! Can someone please help me!!!