Why advertise something you don't have!!!

I went to telkom the grove mall on 22/12/2020 to apply for a new contract for iphone 12 pro max. Application approved immediately and they promised phone will be available the following week. I explained to them that my phone was ****** and I urgently need a phone. It's been almost a month and I still haven't received the phone. My question is why does Telkom advertise something they don't ? I am so diappointed as their new customer. And the branch never even answer their phone, I wonder why they put the number online.