TELKOM CONTRACT UPGRADE

On the 08.06.21 a new phone was delivered and I started having network problems with old phone,when I called a guy called Sihle told me that I need to open a new phone and the Sim card that came with it was the 1 registered to my number so my old Sim is no longer active,so he said I must keep the new Sim on my new phone and it should be activated within 24hrs....till today my phone says emergency calls only,there's no number from telkom I didn't call and I'm not assisted I tried 10213 and 081183 and 181180.the new Sim came with the new phone,all the package must be on the new Sim and I'm keeping my number,I don't understand why I'm struggling with a signal and that happened when the new phone was delivered...can I get assisted if not can I sent the phone back and go get a contract on the network provider that WILL NOT let me struggle this much