I find that when my 9900 is set to 2g or 3g it will only switch from 3 to 2 if 3 disappears and not during a call. Thus if 3 provides a weak signal it'll be a bad line rather than switch automatically to a better 2g. If I am in the middle of a call it will cut off or the other person won't hear me despite there being a very good 2 signal. As a result my phone is on 2 all the time unless i need 3g.

Is this a phone issue or is my carrier to blame?

Thanks