I was offered a voucher of 500 to upgrade to 5G I enquired first to make sure that we have coverage for 5G and was told NO but it can be installed

I was offered a voucher of 500 to upgrade to 5G I enquired first to make sure that we have coverage for 5G and was told NO but it can be installed. Before the voucher expired I spoke to Bongiwe who I reviewed because I was asked to, she gave me excellent service and adviced me that it's the same and there will be coverage in my area. Well.... it is more than 2 weeks already that I paid and and received my modem but NO service only promises that they will come bak to me in 15 minutes which was 2 weeks ago. I phoned several times but no joy. Unfortunately I was to angry to ask for their names as I toik them on their word. Nicky de la Mare