A typical American tire would have something like P215/70/R15 embedded. Would a European/International tire have different tire size embedded on the wheel or it is the same?
Yes, they are the same. However, If there isn't a letter preceding the three-digit numeric portion of a tire size, it signifies the tire is a Metric size (also called Euro-metric because these sizes originated in Europe). While Metric tire sizes are primarily used on European cars, they are also used on vans and sport utility vehicles. Euro-metric sizes are dimensionally equivalent to P-metric sizes, but typically differ subtly in load carrying capabilities.
A tire conforming to Passenger Metric Load and Inflation Tables will have its size represented like this: P215/70R15 97S A tire conforming to European Metric tire Load and Inflation Tables will have the size represented like this: 215/70R15 98S. The visual indicators in our example are no P in the size description (P Passenger Metric) and the Load Index number in the Service Index is 98 instead of 97. Dimensionally they are identical, there are only small differences in the tires load carrying capacity at a given inflation pressure. The P-Metric tire has a maximum load carrying capacity of 1,620 lbs at 35 psi where the Euro-metric tire has a maximum load carrying capacity of 1,653 pounds at 36 psi.
Hmm! You for accepting them!
Going to depend on the laws/civil laws in your area of the world. In many cases they would be liable as they should have known that they should not be doing that.
I think Just Tires have got this wrong. They should not have fitted tyres that were the wrong specification for the car. They should have a set of tables for every make and model of car, indicating correct tyre size, speed rating, etc. They should also have the experience to know when they're fitting tyres of the wrong speed rating. However, proving that might be difficult. They could say that they fitted the tyres you asked for and hence they're not responsible. I suggest that instead of all guns blazing you try to come to a reasonable compromise with the manager, where they upgrade the car's tyres for a price you both can live with. If they're not willing to compromise then you need to contact the local trading standards department.