"Why is service here so bad in the UK and why are they such rip-offs?"
it's not my experience that UK online businesses are bad at customer service, or that suppliers rip you off. It may be yours, but I think you must have been unlucky.
We have some of the world's best online retailers in this country, but every supplier - even European mainland suppliers - have their share of customer services issues. UK suppliers have to operate in an extremely competitive market sector, and they simply would not survive if they ripped people off and provided bad customer service - there's no difference between the UK and Germany in those respects.