Music unavailable for download; do hav primium acct

[christinaU413]

I have paid for a primium account, and have downloaded some songs, but it appears that the music is only available for a short amount of time. Often times, which I try to access the library, it says that the internet is unavailable and theirfore so is the music. This is a Kindle Fire tablet issue. The tablet is on Wi-fi only and does not have a data plan. Any advise?