I just had a client ask me about the possibility of recovering a text message from a year or so back that was on a phone that became destroyed. I told her that the telcos don't keep SMS messages for very long after they are successfully delivered unless they are specifically required to by a court order.
I'm pretty sure that was accurate - VF, Spark and 2DM don't have dirty great archives of all their customers SMS messages do they? And even if they do, Joe Blow with his 021 account can't just phone up and ask them to send him a copy of that txt he got with that hot chick's number from back in June last year (not the question my client asked)?