Just as an aside here, there's no real point or benefit to cancelling until the balance is due.
I'm guessing that would be around March time in this case?
There's a decent chance the tour op (whomever it was, Tui? Balkan?) might have cancelled the holiday due to all the ongoing uncertainty.
If people find themselves in this position, don't cancel until the last minute or close enough.
That at least gives the tour operator the chance to cancel you rather than the other way around, and would entitle anyone to a refund on their deposit.
If you cancel 100 days or 1 day before the balance is due, the liability to the customer is still the same, so as mentioned no real benefit to cancel early.