Xfinity Mobile To Xfinity Mobile User Issues Not Receiving Texts Or Calls Only To 1 Specific Person???

This is a bit of a strange issue so I'll do my best to describe it.  I have been an Xfinity Mobile user since September 2021, having switched from Tmobile to Xfinity Mobile.  I use a Samsung S21.  I've been satisfied so far and have not had any issues and I also kept the same phone number and transferred it from Tmobile to Xfinity.

My Father due to my suggestion also switched from Tmobile to Xfinity Mobile.  He has his own Comcast account, separate home address, separate plan.  I recently helped him activate his new Samsung S21+ and also transferred his existing number from Tmobile to Xfinity this past Saturday on January 1, 2022.

Anyway, it turns out that the last text message that he received from me was on the night of January 1st.  It is also the last message displayed on my screen as "read."  For the past few days I've been texting him and all of these messages say "delivered" but not read.  I also tried calling him tonight and it went straight to his voicemail as if his phone was off.

So I got ahold of him with my Fiance's phone.  He hasn't received ANY of my text messages since January 1st so it is accurate that on my screen they say "delivered" yet not "read."  Also, his phone seems to be working fine.  He can still text ME and see that I have read his messages, he just doesn't see my messages when I reply.  Also I can't call him (because it goes straight to voicemail) but he can call me.

My father can communicate with anyone else including my Fiance perfectly just fine and the same goes for me, I can communicate with everyone else.

I'm just confused whos problem this is.  Is it my problem that my messages aren't reaching him and that I can't call him, or is it his problem that he isn't receiving my messages?  It seems to me that the problem might be on MY end.  Although that's funny as well because I can receive and read his messages, he just never sees my messages.

I don't know where to start considering that he was able to receive my text messages on Saturday night after activation perfectly fine.  And like I said we have totally separate Xfinity accounts as well.

If you have any other questions just ask!