mjandrews96 - I believe the problem may be down to the legal wrangle that's underway between allofmp3.com and the BPI.
I also found this on Wikipedia:
In October 2006, Visa and Mastercard stopped accepting credit card transations for AllOfMP3. "The action Visa has taken is in line with legislation passed in Russia and with basic international copyright and intellectual property norms," a Visa spokesman said. A Mastercard spokesman added the firm "did not tolerate the use of its network for illegal activity."
I stopped using allofmp3 some time back, and now but my audio through www.legalsounds.com.