Telephones in Equestria · 3:12pm Nov 9th, 2017

I just wanted to throw something out there, that while it doesn't seem like it, phones most likely exist in Equestria. Now, I'm not talking about the iPhones that Discord and his clone's had in "Discordant Harmony", any technologies that Discord creates, probably shouldn't be considered canon. I'm talking about in "It's Not the Mane Thing About You", where Rarity says she has to call Photo Finish and cancel her photo shoot. And 'calling someone up' would be pretty difficult to do on the established communication technologies in Equestria (i.e. telegraph and snail mail).
My main original argument I had against this idea, seeing as though cell phones would have had been seen by now, if they were to be used at all, due to prevalence in everyday life, so if they have phones, they're probably landlines. But where are the telephone poles and cables, that are required with such devices?
While that argument is valid, it should also be pointed out, that telegraph has been used and directly mentioned several times, but there are little to no telegraph poles either. Therefore, my hypothesis is one of two things, either the landline and telegraph lines are underground, or they are based off of a magic-based technology in Equestria. Either way, if phones do exist in Equestria, I would date their telephone technology level, at about the same as ours in the 1940s, and 50s. A time where, despite having phones, telegraph and snail mail were still useful modes of long-distance communication.
What do y'all think?