My thoughts:
- if the remote foot switch is still under warranty in the EU, ask the vendor to replace it.
- if you decide to replace the switches, consider buying Carling; the EU distributor is Carling Technologies Switches – Mouser Europe.
- consider replacing both switches in the enclosure at the same time; if one is bad already, the remaining one can’t be too far behind.
- I built my own remote foot switch and used Carling switches and they’ve been working reliably for about 5 years now. You can read more here My footswitch doesn't work right - #4 by persist
- it’s not too hard to replace them yourself as nepali_brother suggests however, if you have an electronics repair shop nearby, you could have them give you an estimate to attempt to repair or to replace the switches. By repair, I mean check that there no no broken or cold solder joints. You’ll probably find that after getting an estimate that it’s cheaper to buy or borrow a soldering iron and fix or replace yourself.