I'm on the 02 network (PAYG) with my 3410. Often I send a message that
doesn't arrive for a couple of hours. Some messages arrive in a
different order. With some messages i send I don't get a "pending"
message. And i'm sure i send messages that don't arrive (although
maybe i might have missed a "message not sent").

Is this O2 or is my phone playing up?

See More: Missing messages