Why do songs I saved dissapear to be downloaded again

[Demeano]

Songs I've saved disappear not from Spotify just from my saved playlist for me to download again I've seen about five songs removed and probably many more that I don't know of its to be expected if a record deal cannot be reached but like I said the songs are on Spotify if this keeps up I'm switching music services I have 300 plus songs and don't plan on keeping track