Look, people are always selling things at the best price they can get. You and the jeweller both did. If you thought you could have got a better price elsewhere you'd have gone looking for it, wouldn't you ? You didn't ? Why not? If you were looking to buy something advertised online for £159 or more you'd shop around on the net to find whether you could get it cheaper, wouldn't you ? Well, that's what you should do when selling, look around.
It may be that the price wasn't all that wrong. If you were buying perfect jewellery at auction (Christies, say) you should reckon it will retail at three times the price paid at auction. In your case, much of the stuff might be only scrap value to the trade or not even that.