Vodacom online contract upgrade booking system doesn't work

I have 3 contracts with Vodacom which came up for renewal at the end of March '22. I decided to use the Vodacom online booking link which asks for your details and the cellphone numbers which are due for an upgrade. You then select a Vodacom venue for the appointment. I chose Vodaworld in Midrand for SUN, 10 April '22 at 12h00pm. I promptly received an SMS and an email confirming the appointment with a reference number advising me to arrive 10 min before the start time and explaining what the procedure will be once I get there. I later received a reminder confirming the appointment. So I arrive for the appointment only to be advised by the security guard that they are not open on a SUN. The irony is that I then received another SMS saying that I didn't honour my appointment. Vodacom needs to update their website to reflect their current business practices - I was livid. Really sub-standard customer service and a waste of my valuable time.