your payment method was declined, all songs gone

HI I have an Ipod touch 5 and for no reason all my itunes downloaded songs are only available via WiFi connection and when i go to re download the songs it asks me to update my payment method and when i re enter my WORKING!! credit card is says your payment method was declined please enter another payment method!! *** apple why do i have to pay for songs i own!! and why are all my songs randomly off my ipod for no reason i have not purchaced anything on itunes in a while i have nothing but problems with apple and have not been able get ahold of anyone decent with support if this does not get fixed my ipod is going out the window and android has a new customer!! all songs are still on my pc itunes but when i sync it the songs undownload off my ipod right when i unconnect!!