Up until roughly May this year, two months after I renewed my contract, the signal I received with my newly acquired Nokia E71 was adequate and I rarely suffered from dropped calls. From then on however, I've been plagued with dropped calls and lengthy signal drop outs. It happened mostly indoors, regardless of whether I was at work, at home or even on the tram. So I contacted 3 Mobile, who advised the phone must be the culprit and took me through the processes. Eventually we agreed I should take the phone in for repair, so out came the trusty old debranded and unlocked Nokia N70.
Within an hour the N70 was also suffering, so I decided to switch from 3G UMTS to 2G GSM, something I was unable to do with my 3 Mobile branded E71. 3 Mobile only provide a 3G network, so when you venture out of coverage, 3 Mobile let you roam onto their backup network (Orange). Well it didn't connect. So I tried manually selecting the network and it still didn't connect. To be sure I wasn't doing anything wrong, when I returned to pickup my E71 I asked the technician to have a look. He said they must have barred me from using 2G as it wouldn't connect. There was also nothing wrong with the E71.
So I called 3 Mobile, who when questioned if they had barred me from using 2G services eventually admitted that they are to be improving their network coverage in my area (Manchester M15) by putting up some new masts and retrofitting old ones. The work is due to be completed by December 2009. Because they are doing this, there will be no need for a backup network (suggesting that the current network coverage is insufficient). The problem is, they've already ended their agreement with Orange in my area, hence why it won't let me access it.
After re-iterating the number of dropped calls and length of signal drop outs, 3 Mobile admitted the signal may not currently be sufficient in my area. They then offered to end my contract free of charge and converted my account to payg two days later (yesterday).
Further investigation suggests that this is also happening elsewhere.
Also see http://www.3g.co.uk/3GForum/showthread.php?t=93511