Due to covid, I got some covid vouchers - they start with "EMD-" then a 13 digit number. The whole trip was canceled, so we have 100euro per person (x3) in AirTunis vouchers.

Doesn't seem to be anywhere online I can use them - is that correct. Anybody with any experience on how to use them?

Incidentally, any tips on cheap fares from northern Europe (i.e. around London).