A complete mess

We've been waiting for over a month now for our OTP mobile number to be updated. Until this happens, we cannot login to our business's online portal to view and pay invoices. The only way one can reset the password is with an OTP sent to your mobile phone (no option for email), but the phone and SIM used by a former staff member of ours to create the account is lost. All we want to do is update the cell number to my husband's number. They are making this way more complicated than it needs to be. The last time I was on the phone with a customer support person last week, they told me that the OTP department only works on email, they do not take calls. Yet they don't reply to any of our emails. It's a complete mess. We are also unable to cancel this contract and take out a new fibre line, so we're forced to work with their archaic system. How can an "internet" company operate like this?