sim cards can only store x amount of sms, usually in the 25-100 range. I know that when I was a Bell Specialist for the Source in Canada, we had a program on a PC and a device that we could plug into about 90% of the phones and transfer vital information between phones, such as sms, contacts and emails. You can try going that route, not sure where you are located, but try out a dealer branded store in your area and see if that helps.