Texts to One Number not Arriving

I have had the same mobile number with Virgin for 4 years and it is
easy to remember, so I want to keep it. I found my daughter was never
receiving my texts, she is with T Mobile. She can send me texts but
not v versa.
I left Virgin and went to T Mobile. At first we texted each other when
I was using the number given me with the T Mobile SIM. Guess what
happened when I PACd my old virgin number over? I went back to
squareone, she still could receive none of my texts and we were both T
Mobile.
T Mobile could not resolve the issue so I left them and went to O2.
Now she is receiving texts from my O2 SIM and the number sold with the
SIM. Today I started the 7 day PAC process which will bring my old
Virgin number onto the O2 SIM. I am not too confident the texting to
her phone will work............

Has anyone else had this problem with inability to text one isolated
number? She has not barred texts from my number, at least not
knowingly, and so far as we know text barring can't be done on her
phone

My phone is a nokia 8310 hers is a 2310. I have not swapped phones
through all this saga of weeks, I am only buying SIMs.

Textless