Another thing, if you look at the specs for the Tiger River spas, you'll see that they carry the service marks as follows:
Electrical Safety - ETL and CE Listed
So for this product they didn't even use UL. (I don't know why anyone would as UL is the most expensive mark to obtain. ETL is much more cost effective and similarly well recognized).
Now that you've been educated on the safety markings used on customer products, I wouldn't necessarily kill yourself over the price you paid for your tub. Especially by calling ANOTHER dealer AFTER you purchased it!
Of course... call me up and I'll sell it to you for $50 less... That is if you want to buy another one!
(see what I mean?

)
Enjoy your tub and have a great time in it!