the problem with roaming is that problems can arrise at any time and yes do tend to sort them selves out.
its hard to beleive that in this day and age we have these issues. But there is no gaurentee that whe you text another country that the person at the other end receives the text.
Its all to do with how networks interchange with each other.
No real answer im affriad on this one.
Lodge a complaint with o2 and ask for one of there tech team to deal with it.
Worth a try
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