Firstly, I wish to register find slurs against people in whose country one lives offensive and unacceptable. I have had many a similar experience with Mobile shops and suppliers in the UK!
I suspect your problem may be down to the pre-paid package you were supplied with.
Can you tell me which one on the following page you purchased?
Which network is your mobile MEO sim trying to logon to in the #UK?
It should be one of the following:
Vodafone, O2, T-Mobile, Orange,H3G
If it's not configured to do so, you will need to reconfigure it to do so.
Finally, are you topping up your MEO mobile package regularly as MEO usually requires a minimum top up every few months! ?