96W Rated Tires for Active Hybrid 5 from Dealership

[Coupe E36]

I purchased a used 2013 Active Hybrid 5 from a dealership last October. It came with (4) DriveGuard 245/45/r18 96W. I live in southern california, and we've had extreme rain storm these past couple of days. This morning my little brother drove it, and the side wall ripped (see attached image). I took it to a Tire Shop and they have the tire in stock, but they said their policy prevents them from selling and installing this tire on the car because its not the XL rating, though I have these same tires on the other (3) wheels from the dealership I purchased from.

Is there some truth to this, or are they trying to pull my other leg and see if it plays jingle bells? I can't imagine a BMW dealership selling me a car with incorrect tire rating on all 4 that prevents me from purchasing a replacement of the same type. And this shop are the only shop open this late, so I can't call anywhere else to confirm. If this is the case, then I will have to bring the car back and demand them replace all 4 since I am not forking out 300-400$ each tire to replace. Unfortunately the BMW dealership I purchased from is having phone issues so I cant get anyone on teh line to confirm, and so I figure i'd ask the members here.

Many thanks in advance.