Cold water faucet + drainage connection for washing machine

You never said that.

You could now complain that you did not order this and the company acted without a contract. You could demand the dismantling, legal advice is available from others...

Or you accept it. The costs are not grossly exaggerated, tick it off and move on. In my opinion, it is not worth the nerves.

Tell him that and also that you would have spent a maximum of 200€, otherwise you wouldn't have taken it. Either he admits that it was his mistake and is glad to still see some money without much trouble, or you agree on something around 250. I can't imagine that he insists on his full price without any offer.

yes, 200€ would have been more of a maximum expectation...

What is an inlet pipe in connection with a washbasin and where is it installed?

Specifically:

Inlet pipe 1 1/4" x 200mm chrome-plated with hose fitting.

The grey pipe is the drain coming from the siphon. Or is it the vertical pipe that goes from the sink drain into the siphon?

Thanks!