<prompt> Human: If I over pay on my credit card say I have a balance of 100 dollars and I pay 200 do the credit card companies have to pay interest on the surplus 100? Im in canada if this makes a difference.  <response>: If I over pay on my credit card say I have a balance of 100 dollars and I pay 200 do the credit card companies have to pay interest on the surplus 100?No. 