For years people have been saying do not use an ISP provided email address and then the business people that do it :(
a 3rd party free email provider , like yahoo . Or the original hotmail back in the day
Both were pretty bad, ( both were used by Xtra for their free ISP provided email service)
You do have a good point , its been well known that ISP free emails were often substandard . Theres no excuse to start complaining now.
People have email adress's from long long defunct ISP's (eg paradise, clear) , did nothing to move to another email service & stayed with email adress from dead
ISP's & now start to complain.
So those complaining , look in the mirror 1st.
Theres no reason an ISP couldnt have a reliable email service, ISP's do offer paid email services that are often good.(maybee just OK)
Its the free email a/c they dont seem to care about (not just Voda)