Its always best to try and resolve the issue but be prepared that it may take longer than two weeks for communication. As stated on here they could be on holiday or ill.
Its often best to give it a month or so because you can always name and shame when you`ve had enough, you never lose that option.
If you cant get hold of them try searching on the net for them, facebook etc, its surprising what you can turn up.
Had this happen to me once and the guy ignored me until i tracked his misses and kids down on facebook and pursued him through her. He soon sorted it then.
Nothing like being a psycho stalker to get the family worried....