Emails disappearing into thin air, missed deadlines, major embarrassment and income compromised.

I really hate having to do this but I am not winning with support and I know this is the only way to really get my message across. From Friday most of the mails I sent never arrived at their destinations, I did not receive any undeliverable notifications. I have not changed any settings and it has been (mostly) working without issue prior. This has caused major embarrassment with missed deadlines due to links not received, as well as invoices not being delivered to my clients and therefore compromising the livelihood of myself and my employee and causing damage to cash flow. Support is basically dysfunctional with generic copy and paste style responses - I have been emailing them all day with screenshots of the error messages on Cpanel email deliverability and other communication but apparently NONE OF IT GOT TO THEM which is the grand irony here. I am beyond irritated and am just going to use Gmail directly going forward. What is the point of having a domain to conduct business as a professional company when it DOESN'T WORK PROPERLY? I also see that the DNS points to some other server that has nothing to do with Afrihost? Why did I pay the co.za renewal and who is in control of my domain? My entire configuration is a mess. I used to champion Afrihost as the best provider in SA but I have been sorely let down. Please fix this urgently!