Payment for Apple Music.

Hi, I need your help. Three month ago I started free-subscription for apple-music, this period has left 28 february, and 1 march I made payment for month-subscription. Payment has done, and I started using Apple music, but now sometimes(every day) apple-music bill comes and tries to make a payment. He-he, I don't keep my money on card, so payment don't end, but say me, why I have a bill? My month subscription have all march, including 28 march.