Campagnolo Shamal trouble

A few days ago I received my Eddy Merckx MX Leader which I purchased from an on line shop in Germany (for a significant sum of money).
In general the bike was as expected (i.e. quite nice) except from the Campy shamal wheels!
The wheels was supposed to be one of the highlights of the bike, hence driving the price upwards.

My observations with the wheels were the following:
· Spoke tension was very inconsistent
· Some spokes were very very lose
· I could see small cracks near the cut out for the inner tube valve.
· The rims have a couple of small dents on the braking surface.
Problems were much more severe with the rear wheel.
I tried to ride the bike and it felt very wobbly and unstable. I could actual hear noise from the spokes heating on each other.
A soft push on the rear wheel either to the left or the right would move the rim several centimetres of axis.

I took the wheels to my LBS for tensioning/maintenance.
When I picked them up they mentioned that they could not get all the spokes tensioned as the tensioning nuts of certain spokes were stuck.
They tried several solutions to make the nuts loosen but they could not get all of them moving!
They mentioned that if they applied more force the spokes would break.
They also mentioned that they consider the wheels worn, with not much life left in them.
They pointed to the small cracks on the rims (around the cut-outs for the spokes and valve) saying that I should be careful as they are bound to make the rims crack at some point.

I contacted the seller, who responded that he dismisses all the above claims; he mentioned that all bikes are serviced and checked before shipping!

What is your view on the above issue:
· Can I do something to improve the performance of these wheels?
· Do wheels really have a useful life limit, after which functionality deteriorates significantly?
· What would you do with the seller?
Many thanks George

Below I attach sellers pictures. I will also provide my own close ups later in the day: