I keep getting the same text/calls from friends and I don't know what it does

When that happens in my game, anywhere from a few hours to a day or more my Sim will get a text from who's supposed to be the Sim that wanted to meet them, and then that Sim gets added to the friends list as an acquaintance.

You can choose to befriend them or ignore them from there on out, but other than that, it really doesn't provide any gameplay or have any consequences.