Mahanagar Telephone Nigam [MTNL] — prepaid sim card deactivated (using for more than 10 years)

Prepaid sim card #[protected] got deactivated on august 2nd, 2020 without any prior intimation. This prepaid sim holds balance around rs. 143 and has been distributed this number on various critical essentials. For example gas service. Even though i was using this number on a regular basis it got deactivated after using for more than a decade. And now there's no customer service for this. Even their self service portal doesn't handle such requests and customer care no. Isn't connecting. Are you guys dead or what? If not then please resolve this query. This is a critical number for me and if you don't wanna service than let me port this to some other better service provider