iPhone 5 speech goes bubbly, calls drop, failed SMS, yet good signal
A couple of months ago I moved my existing mobile account (giffgaff.co.uk) from a Nokia feature phone to a 2nd hand iPhone 5 which I'd revived with a new battery.
After sorting out a problem with unreliable mobile data by forcing an APN settings update, I still have problems with speech and SMS.
Voice calls frequently degenerate into a bubbly sound before being dropped. Often this happens as soon as the connection is made, or within a few seconds. It happens equally if I try calling my voicemail.
Also, it often take several tries, sometimes many tries, to get a text message to send.
In all cases I have several blobs on the signal strength indicator, so it isn't just a case of a weak signal.
Any ideas, anyone?