E-SIM MTN

I bought a new phone at iStore on the 28th of April, with a contract and unfortunately the sales lady didn't ask me if I would like to keep my old number and gave me a new sim number with the new phone. I have been to MTN store about 3 times and to a MTN store in Eastgate to get a e-sim. Until now I couldn't get a e-sim from them. I tried phoning their customer service but they can't do a e-sim, because I must do it at the store. I really don't know what else to do