Well, if it was someone tricky, they would bill the LL and get some cash free from you on the side. When you complain, they can deny everything. They have your money already, so there's nothing you can do.

Agreed. It's obvious the caretaker is a bit of a bully and with a newbie family just moved in you seem like easy targets for him.

I would also recommend moving out. Personally I find it's vital to be comfortable at home. It's your place to relax and chill out and life will become so stressful if you constantly need to fight him. I would also recommend to contact the mieterverband. They'll be able to advise you on how to procede-also regarding the washing room. I'm pretty sure that he can't refuse to let you wash.

Won't work I'm afraid. You can't do it this way, the landlord will have his own contacts for repairs anyway. He'll simply send the invoice on to you as you ordered the plumber and it's your responsibility.

When we've needed repairs to things in our apartment, we've always contacted the agency responsible for our building (our building is also owned by a big company) rather than the Hauswart. After contact they usually send us a letter stating that they have given the order for repairs to be done and the contact details of who will be doing the work. Til now we haven't had to pay (touch wood!!).
Maybe you've lost the money this time, but I think I would get advice from the renter's association on where you stand regarding repairs and the use of the laundry room. I don't understand why the rental agency is not taking your complaints more seriously but I'd guess with back-up from the renter's association that might make a difference.

...and for those who have questions about their rights and don't live in the Basel area:

http://www.mieterschutzverband.ch/xm...t/de/intro.cfm

They have a hotline you can call at a small cost.