UPGRADING MY CELL PHONE CONTRACT

I am due for an upgrade since March 2020. Just before lockdown the Cell C agent told me I can't upgrade due to the lockdown. Now, for the past two weeks, since 08 June 2020 I am trying again to upgrade my contract but with no avail. Every time all the agents I have spoken to have an excuse and that they will call me back, which never happens. There is also a month-to-month contract on my number that first needs to be cancelled and also there I get no response and or answer. I again phoned today 12:38 and 12:47 when an answering machine tells me that I am phoning out of office hours ????????????????? Can someone please help me since I am not a new client of Cell C and has been a customer for over 10 years now.