Sorry about the delay. Been otherwise occupied recently. Looks as though the German site is no longer available. Bit of a bugger. They were very cheap. 200 Melatonin for £4.68 or thereabouts. I first bought from them through Amazon, I think. Might be worth a look. Sorry I can't be of more help.
Edit. Just checked Amazon. They only resell and seem quite expensive. I also checked domain names. Pipingrock.de is taken, but no longer active, so I don't know what has happened.