Hi Spinal,
As far as I am aware, some insurance companies exclude coverage on some home ‘infra’, if there is DIY involved. Some localities even have rules that you must hire a local company (e.g. electrician, etc) … Hence my comment…
As a home owner in Switzerland, I am painfully aware of the challenges you are facing. I was a home owner also, even before the days of big German DIY stores around zurich. Made many trips to germany and ‘conversions’ from Swiss sizes to German sizes… lol …
Regrettably, this industry is highly controlled by small businesses. I’m painfully aware of ‘you need a dedicated firm to gouge you’ mentality. Just as an example, I wanted rocks for my aquarium. I could not believe the prices, even bulk prices. Eventually, i got lucky when I walked into a rock supplying company for construction. He was a good guy, asked me what I needed the rocks for, gave me good advise (i need rocks that will not continuously cloud the water) and sold me the right one at close to bulk price. That dec, i stopped by his store, thanked him with a bottle of wine, showed him pics of the established aquarium and had a chit-chat with him. He then asked me how to save money because he was going on holidays soon. I suggested that he overpay into his credit card, use the credit card instead of withdrawing cash from ATMs …
There are good guys/companies around. You have to hunt. What you save in CHF, you pay for with time, resources and emotional/psycological weight… but it builds your local network. These people can and will refer you to others … that’s one way the Swiss do it … It’s rough going at first …
I think you would be better off calling the company customer service. I think you will get better results with phone calls than emails. They may ask for the serial number… Ask them for installers/ repair companies in Austria/Germany… If you can talk to one of the technicians/engineers, then they may be able to give you suggestions, perhaps even point you in the right direction (as opposed to first level tech support who will, may be, open a case and send notification to someone) …
Swiss people/companies, as you are now well aware, are much less likely to bother to sell you the gasket, since the ROI is very small. Perhaps similar companies in Austria/Germany (being remote) are more willing to help, sell and mail you the gasket?
All the best … Cheers …