I recently had an instance where I was out of signal on my Orange network C550. Someone on a 3 network mobile sent me two text messages during this time and I did not receive them. Not then. And not subsequently.
When this was discussed we then experimented by turning off each phone and sending a text to the other phone. The Orange network recovered successfully from the "outage" and delivered the text when the 3 phone was then once again turned on. However, the text sent from the 3 network phone to the Orange phone when it was off did not arrive.
Has anybody else had this experience?