Firstly raise your official complaint with BSNL, get complaint ID/ticket ID, if you do possess as you have already complained before then use it as a reference.
And on X, tweet tagging BSNL and other concerns handle and DM to BSNL
Then try raising your complaints here in order one after another, keep some gap, wait for a reasonable time before registering on another:
https://pgportal.gov.in/signin
See if it help, will help further in case when you won't find any results. I hope, it will get resolved atleast PORT will be successful.