Cell C WiFi Calling

Earlier this month I called the tech desk with regards to my WiFi calling not working, I was advised that this was due to a new patch that Samsung pushed in the latest android 7 update, I then downgraded my S7 back to android 6.0, WiFi calling was working, now this week I once again have no WiFi calling.

When I called tech support tonight I was advised that the issue is still ongoing on both the S6 and S7 and was advised that there is a article on the internet about the certificate issues and Samsung are attending, I searched for over an hour and could not find a single article about this or any other user complaints.

When I called back and spoke to another agent requesting that the URL of the so called article be sent to me, he knew nothing about it and advised that the S6 is no longer affected and I need to chat to Samsung to get further updates. Surely if this was a global issue there would be something on a forum like my broadband?

I live in an area where Cell C refuse to do any work on the towers to improve normal GSM calling thus rely on WiFi calling for my standby shifts.

Please advise what is the latest updated as well as when this will be sorted because your tech support have no idea.