Wow! I guess labour was another 200E or thereabouts! That must have been a pretty scary bill in total with your rear sprocket too!
I nearly bought an Aston Martin DBS a few years ago but didn't fancy the 2,500E annual service bill. But a 3W is getting pretty close to that if you're unlucky.
I very much hope that your little car starts to behave itself now, and that 'fixes' for these rather expensive items that are lasting quite ridiculous times are found.