So-called debt after 3 years with no request or notification

I have not been a member at Virgin Active since 2017 , now during the COVID 19 crisis where everyone is under enormous financial pressure I receive a demand letter for R 1800 for an outstanding Virgin Active account.

The call center for Virgin Active and the so called debt collectors VVM are closed.

This is disgusting and in bad taste , Virgin is a money monster and they can forget about the R 1800 , I will not pay this