These things don't phase me, whether I'm in a relationship or not. Reasons for this is because people usually don't have wrong intents doing it when it comes to not calling back. The only exception for the alternative behaviour as far as I can see is when it's really important. Then again, importance is a term defined differently by everyone.
Taking that into consideration, I don't think this sort of thing should phase you either. Don't let the small things bother you, as it'll become increasingly irritating, and shadow your content more often.