I'd say if it bothers you, contact the vendor and return it or at least discuss with someone. While 5 months is still within expiration date, it's kind of short. Regardless, if you aren't pleased with it, that's just it. It'd bother me if I were in your place. I know of two other vendors who sell short dated film but they advertise it as such and discount them.

Do you plan to consume all of the film in 5 months? I typically don't as I keep enough stock here on hand.