Are they still in your country's store, and do they show in the Purchased tab in the iTunes store app on your phone for redownloading, or if using your computer's iTunes the Purchased link under Quicklinks on the right-hand side of the store home page ? Whether music will show there will depend upon what country that you are in (music can't be redownloaded in all countries), whether they are still in your country's store (any item could be removed by the rights-holder at any time), and whether they are hidden (hiding and unhiding) - if they show but don't have the cloud symbol for redownloading then are they still listed in your device/computer's library ?
(These are user-to-user forums, you're not talking to iTunes Support nor Apple, and you are only guaranteed one download of each item.)