After receiving further text messages and one phone call from the aforementioned strangers, I got a text message this evening from my friend Casey. She texts me from her husband's phone because she always loses hers. I have neglected to save her husband's phone number, mainly because I'm afraid I'll call or text him, trying to reach her and he'll be at work in an important meeting or something (in fact, I think I've actually already done it).
Her husband's number and the aforementioned strangers number are quite similar.
You can guess what I did (at least I wasn't rude).