I recently bought songs from iTunes and every time I go to listen to them they get deleted. I'm able to re-download the songs but they don't stay on my phone for more than an hour.
Apple tends to do this because of competitors, I have been going through this for months now and have had at least 6 songs deleted. I downloaded them again, and thankfully apple had let me get them for free. but now, apple is making me purchase them. I am fed up. but heres a tip that hopefully help you out, download them on another website or platform. try not buy them on iTunes. I hope this works for you. and well wishes to you. ;)