Is the bank entitled to demand that I pay interest on the Visa card I obtained in 1413 AH, given that I have repaid the original amount and more, and that the remaining amount consists solely of interest?

Legally, one is not required to repay the interest on an usurious loan; rather, repaying the principal alone is sufficient, due to Allah's saying: ﴿And if you repent, you will have your principal. You do not wrong, and you are not wronged.﴾ Therefore, the bank is not permitted to take more than the principal, and you are not permitted to voluntarily pay the excess. You should try to reclaim what you previously paid in excess of the principal. If you are unable to do so, then refrain from paying additional interest, unless you are compelled by an unjust judiciary that would inflict punishment upon you.