Bought a front motorcycle tire and a rear motorc...

Bought a front motorcycle tire and a rear motorcycle tire off Ebay, which was being sold by inland_atv. inland_atv messaged me letting me know that the items weren't in stock. Long story short, they refunded the monies for one tire(the front), but failed to refund the money for the rear. These tires were ordered separately, not at the same time. My bank statement reads an outstanding balance debited by inland_atv. They insisted the refund was for just one invoice. Why would my bank statement state that an separate amounts for both tires was taken out, but only one invoice shows a reason for a refund? inland_atv conveniently slithered behind Ebay and it's policy's. Bank statements don't lie, inland_atv!