Hi & thanks for your prompt reply.
The phone is a Motorola G31 64GB (Model number: XT2173-3) which I bought from Argos.
The old phone was a Motorola Moto C Plus
Unfortunately the old phone suddenly stopped working after locking up occasionally over then previous month, otherwise my first option would have been to revert back to that phone.
This is why I had been so pleased with the replacement as for the first couple of weeks as it had worked perfectly with both texts & voice.
As I am housebound & severely ill (unable to speak easily a lot of the time!) I rely on text messaging for keeping in contact with my brother who acts as my care helper.
As I was an IT professional for decades before I became ill, I have used much critical thinking to try & understand this problem. For example why it should suddenly stop receiving texts suddenly after working for almost 2 weeks, why it receives texts I send to myself perfectly when those text still have to enter the Virgin network & why I can receive 2FA texts from one bank immediately every time unless perhaps they are also within the Virgin network! I am also confused as to why the texts I send always reach the recipient immediately, but I can't receive their replies.
One other thing that has crossed my mind is that about a month or so ago, whilst I was still able to use my old phone I received a notification that my phone had automatically been switched to a SIM-less phone, when suddenly I started receiving a full strength signal. I have been wondering if this has somehow interfered with the phone swap, although the fact it worked fully for almost 2 weeks is a bit confusing!
I hope you can offer more advice as to how I can proceed.