Unfortunate that they didn't make clear they were intending to drift away, but perhaps it just happened.
Call once by all means, but a 3 year gap suggests they've moved on, even if they do think of you occassionally. (I've old friends that I occasionally think about and wonder how they are, and wouldn't mind getting in touch with, myself.)
If you contact once and they wish to remain in contact then the ball is in their court, technophobe or no technophobe. But I've little more to add than what's been said above. Don't expect a renewal and a return for how things once were. That is now a memory.