I have sprint but bought a Verizon iPhone?

Now I researched and saw that the iPhone 7+ would be able to accept my SIM card, (which it did) have my bars and LTE and everything. Didn't try surfing the web, but I tried to make a phone call and it say my account could not be validated. What do I do about this?

I'm afraid you're out of luck. Sprint won't activate any phone that isn't build for their network. The phones just arent interchangable between carriers as they are on the GSM carriers, such as T-mobile and AT&T.