Un responsive tenant

Rent Arrears

My tenant has stopped paying complete rent from the past 5 months (Paying only 1000 of the 1890 monthly rent). He claimed he has financial issues (his daughter goes to private school and has 2 high breed dogs with a savings account balance in excess of 30K GBP at the time of contracting in Oct 2020) but simply refuses to engage in any discussion of any nature including payment plan...for the last 4 months, he has stopped responding to mails, stopped picking calls, refused entry to the property (even for Safety checks like GAS Safety and Security alarm ). My agent issued a Section 21 notice which has a target date of 18th October 2021(Tenancy agreement also ends 16th October 2021), however since the tenant has stopped any communication with us, we do not know if he is going to vacate or not and as such don't know how to collect the keys...Unfortunately due to the pandemic , I am stuck in India and cannot return till possibly Jan 2022. My agent has written a formal mail to the tenant identifying a friend of mine as the designated person to collect the keys and discuss the date and time of handover, but the tenant is refusing his calls too....Please advise what my next steps should be.