SIM SWAP Could not be done

After using MTN for 15 years I decided to upgrade my SIM card to a micro Sim. i contacted the help line 135 and an agent asked me questions about my number which i gladly responded to. However she then asked me to give her the question and answer that I have previously set. I couldnt remember the question since I have never done a Sim swap before. All she could say was she cannot help me with the SIM swap if i dont tell her my question and answer. I requested her to ask me the question so that i can answer, but she didnt. I dont know if i was supposed to create a question and answer or give her a specific question which i might have given in the past 15 years of using the number. communication s****s are important i felt like leaving MTN after the call.