Why are all my magazines in library gone?

Ive used this app for months and Ive loved it. I never even read my print subscription anymore because I always have my iPad 2 with me. I just went into library to download July and all the previous months need to be downloaded again? Why? Nothing has changed on my end. Same iPad. The signal to my Internet is low due to where I live and it took me forever to download those! I wont be able to do it again and its a shame because Im always rereading relevant articles. I love parents magazine but this disappoints me.

Koltsmama about Parents Magazine