Hi,
My first recommendation is to find out what the problem area is. Based on your post, it sounds like it could've been the phone, battery or even charger.
If you have a friend with another Sony Ericsson phone, you'll likely be able to test the charger, and maybe even the battery. Once you know what the problem area is, you can contact your local office for a possible replacement battery/charger (depending on the process in your country).
As for the phone signal issue, we would want you to try the update service application first, so if the issue concerning power is NOT the phone, please do try this also.
Hope this helps!
