I have had the exact same porblem. and Also EVERY day they tell me to dele mail from my webmail account or it will be trashed. I think after 57 years I am done
that is why I am trying to find a new server for land line and mail etc
After having Telkom email for decades, usually problem-free, it started giving me problems towards the end of last year. With their so-called upgrades they have been doing on it for months this year, it just keeps getting worse. Many times, I can't access it at all. After the SMS, about 2 weeks ago, saying I must contact Telkom to change the password, everything worked fine for about 2 days. Since then, I can receive email at times, but not send at all. I am now changing over from Telkom email to outlook.com, and gmail. Phoning technical help resulted in the call being disconnected at each attempt; after weeks of trying, I managed to log a fault yesterday. I doubt if anyone from Telkom will contact me.
When Telkom discontinued copper phone lines and ADSL lines in my area, I changed to Cell C's prepaid Anynet calling plans (eg R200 for 15 hours, valid for 30 days), and Cell C's prepaid Gb valid for a year. The Gb are loaded onto a sim card in a portable/mifi modem also bought from Cell C. I have had zero problems with my Cell C products, and usually good customer service when I need it.
There are also very good fibre and LTE options becoming available all the time, eg Mweb and others offer Telkom/Openserve fibre starting at R399/month. Mweb also offers email. Vox Voip unlimited calls start at R175/month. I see all the cellphone providers are offering good LTE prices, as are ISPs like Mweb, Afrihost, Axxess, etc. I see that MTN has new 'Made for Home" fixed LTE 24-month contracts, eg 75Gb anytime +75Gb night data, R400/month, 110 anytime + 110 Night Gb night Gb R500/month (see page 18 of MTN's July 2020 'Yellotrader" magazine, available from their website and shops)..