Who I have the same questioned this topic

So a year or 3 ago i had an issue with message+ where it would send duplicate text messages from anyone using an iphone to my android. I uninstalled the app, and started using handcent, i had my phone replaced for a hardware issue a few months back and decided to try message+ again. And here's where i ran into a new glitch. If i have the message app open, and text someone, i get no notification when they reply. So if like i text a friend, then set my phone down and go get a drink and forget to look to see if there's a new message, i may miss that message. I had my son text me with a semi-emergency but i had the app open, so i didn't get any notification he sent a text. If it would have been a real emegergency that could have been bad. Talking with co-workers this happens to them also, issue is happening on my Pixel 2 XL, my friends Pixel 3, an iPhone 9, a Samsung Note 9, and an LG v10, so it's not specific to any device. I'd rather use Verizon apps as i trust Verizon, kinda still anway, rather than a 3rd party app. Fix please?!?