Postpe — Harassment by the collection agency & unethical means used to use my contacts and defame me

I had used the aforementioned companies credit card and failed to repay back due to severe medical expenses. Had informed the nodal officer for the same. Their collection agencies have been calling me from
+[protected] & [protected] numbers and have been calling people from my contact sphere and misleading them about me meeting an accident and asking them to pay.
The complaint have been raised to the postpe authorities as well but it seems like falling in deaf ears.