Q: Billing Info needed in order for me to update or download free apps?

Two weeks ago I began to experience problems with my Apple Account, if I ever attempt to update or download any apps, it will come up with a message "There is a problem with a previous purchase," I later clicked on "Billing Info" to find that I needed to insert a credit card, I do not have a credit card! I checked my account balance expecting it to be negative something to find it was "$0.72," this issue is driving me insane, I currently have 11 updates on my iPod and 3 updates on my MacBook Pro (Including Yosemite which I was extremely excited to get), I am very disappointed and now apps are begging to close mid-way through use or not show images etc, so if you could not already tell my question is how do I fix this without getting a new iTunes Voucher (Getting a new iTunes voucher was a solution to the same issue that happened a couple years ago). Thanks for your answers!