Here's the problem - I am trying to send text messages to my dad, who is currently languishing in the care of a hospital a fair distance from where I am. I thought text messages might be a good way to retain some kind of contact, but apparently not. Apart from two last Sunday, all of the messages I have sent him have not got through.

I am on O2, as is he. And, I'll add, are my sister and mother who I have been in contact with via text message v the at few days. They are getting my messages, but my dad is not. Today, I ran a test with my sister and my dad's phone. I sent a message, and it did not get through. Something, somewhere is stopping me messages from getting through. He is able to receive texts from other people, including my sister and mother.

Went to the O2 shop today, and the "guru" said that his phone is blocking my number. I asked my sister to look, and she told me that it was not.

So something is stopping me from getting messages through. I know I can prefix the message with *0# to get a delivery report, but from what I can tell,Mathis just confirms that the message has passed through O2's network. It doesn't confirm that the message has been sent to the one.

O2's Twitter support has dried up. They asked one question (was I using +44 in the number - answer was no, I am not) and I have heard nothing since.

I am probably just venting here, but the problem. Has not resolved itself, I am aware that a number of messages sent since sat Sunday, and indeed a few before then, we now not received, and I am rather angry about that.

As O2 seem to be unable to help or advise, I was wondering if anyone he could suggest things to try. Just remember that the recipient phone user is not really in a state to start fiddling with his phone, and if my sister is the she may be able t try things with it, but it's a slow process.

Does he receive messages from other people OK? What kind of phone does he have? If it's a "traditional" phone, is the inbox full?

My money's on a network error TBH, I'd recommend phoning O2 and seeing if you can get past their first-line support monkey onto someone who can actually help you.

Does the phone work with someone else's SIM in it? That would be a good way of proving if it was a phone or network problem, I'd have thought?

You've proved it's not your phone, since you can send to other people on the same network.

You've proved there's nothing technically wrong with his phone, since he can receive from people on the same network.

If it's just a few messages gone missing, then I would blame network congestion in which case they'll probably turn up a week later, or end-user error. He might have simply deleted them by mistake.

If it's all messages since a certain date, then the only logical explanation is that he's accidentally blocked you around that time. Depending on his phone, it may not be that simple to see who is blocked so your sister may not have looked in the right place.

You do have his right number, don't you? Try replying to his most recent text to see if there's some weird format issue.

We found the problem - my number was blocked. It’s hard to diagnose such things long distance, especially when the person on the other end is full of post-operative painkillers. My sister was trying to see what she could find at the time, but didn’t find the block list. He had probably mashed the keyboard at some point and done it.

All sorted out now, which is good.

I didn't even know you could set up a block list on a phone.