Why is my purchase history cut off at 26/02/12 ?

i first created my account on 25/12/2010 when my brother gave me his old ipod and since then i used the app store very often but until now i did not realise that my purchase history has dissapeared and i cannot see anything before 26/02/12 which is a real pain. I have looked on the app store at the apps i know i bought such as Doom Rpg and it now says i have to repurchase it. i dont know what happened to my account or why it is saying ive never bought anything before the above date. I have also tried it on the latest ipod abd checked my purchased history on there aswell but it is still capped.

Many thanks.