My neighbour broke her keys off in the lock to her flat. No problem, she knew what to do: ask for…read morehelp. However, the repair proved to be beyond our skills and we had to call in a professional. We phoned at Fischer's (it's app. 8km away from us), and they were there in less than an hour (having announced the slight delay beforehand), the repair was fast, painless, friendly and not really expensive (altogether around 60EUR). The advice in the shop was spot-on and as added bonus, we found that the shop had a greater variety of screws than the big hardware stores in Darmstadt.