Vodafone - Distress and Inconvenience due to poor service

I have a postpaid mobile phone service with Vodafone. The Missed Call Alert (MCA) also known as Missed Call Information (MCI) service has not been working for several months. Due to Covid situation I am working from home, and I might have missed several important calls because I don’t get MCI messages on my phone.
Since November **** I have written numerous emails to Vodafone and also spoken with several staff members but until today this issue has not been resolved. I have even escalated to their Appellate team but even they have not done anything. Whoever I speak with gives me a false promise that they will look into it, will call back or get is resolved in the next **-** hours but they are all lies and false promises.
It has been almost more than four months, I am not getting any missed call notifications, I may be missing important calls and this is impacting my work. I feel really frustrated and this has caused me immense distress and inconvenience.