Can call but can't text a person on new phone?

I just bought a Samsung J7 refine through Virgin mobile and there's an issue. One person on my contact list isn't receiving my text messages even though calls go through just fine. This person has an iPhone (I don't know what one) through sprint. Every other contact I've tested has worked with the texting, including other iPhone users. I've tried adding a 1 in front of the number but that didn't help. I also have yet to verify if her texts are able to make it through to me or not.

Have them to reset their network settings then see if they get your text message