I know it's not a dream but... Am I being spoofed?

Okay, so thing is back then in 2016 my phone number called my sister's phone, and no! I did not have a data plan, and I still don't. So on Wednesday I was just really bored and was playing around, so I went to my default messaging app and tries sending a message. And of course it didn't work because it's no data plan. So I went to my messaging app that I use now (Nextplus) and I texted my out of service number and I said "Yo!" So then yesterday, I plug my phone up, power it on and the next thing I know I look in my notification bar, I look at the Nextplus text and it says.... "Yo" and of course I'm freaking out like "OMG what the heck is this?! So me being curious, I responded back with "Oh jeez! What the!? OK, I don't know you, but I was just seeing if someone else actually had my number, that I cannot use anymore." So uuuuuummmmmmm.... Can someone kinda help to explain what's happening? Also the reason I don't write in the dream journal is because, when I press it, it presses the button search.

I'm not exactly sure of what's going on, your post is a little unclear. It sounds like the message might have sent because it wasn't an SMS. If you try sending a picture or an overly long message, it gets converted to an SMS and requires a data package to send (or receive). Sometimes phones default on sending an SMS even if it's a small message, and it could be possible somehow yours was doing that and suddenly had that option changed somehow? About your out of service number receiving a message... I'm kind of stumped. Maybe both phones were connected to your wifi and the message sent out via wifi because an option that allows for that in the app you use? That would explain why your message actually sent without a data package too.

The app does use WiFi and I understand what you mean, but in 2016 I still had the app then, yet I didn't use it a lot, so my out of service number called my sister's phone on the Google hangout app (I meant to add that in). We picked it up and no one answered. Hopefully you'll be able to understand this part better, lol! 😅

I think its possible that your phone # has been re-assigned. Check out this article.

Service providers recycling cell phone numbers is a dirty little secret - SFGate