Nextra Teleservices — Nextra refund

Sir, my registered mobile no is [protected],
after so many complaints my refund of 1700 is not done.
i have cancelled my account but its 4th month no one came to collect my router and my refund.
after 9 months lockdown when i came i called costumer care to ask whether i should recharge or not..she said to recharge and your wifi will start working but it didn't worked.
please help me out or will complain on legal backgrounds.
Thanku.