Complaint

I went to Mr price on Wednesday here in tembi mall and I purchase some item and I pay using my mrprice card and after paying I was given a slip to sign and I sign and the cashier told me the signature is not the same as the one onthe card and I tried to explain to her that this is my card and I've been using this card from last year and she called the manager and the manager came and when she saw the signature she started shouting at me telling me I am doing ***** and everyone inthe store was just staring at me as if I stole something and I try giving her my id she say she doesn't want it and she took my Mr price card and went wth it and she told me to leave or she will call the security and I felt embarrassed as this is not the first time encountering incident like that in that store and my opinion was she is the manager why did she fail to take me to the office and call the relevant department to do background check..I've been calling since the day ofde incident to the customer Service and I was told I must write email and I did and they never responded and even today I called and I was told they will tell the district manager to call but still no call..