A buyer bought a lot of 4 pair shoes and paid right away the total amount of $36.00. She messaged me to say she did not want one of the pairs so to not bother sending it. Because the shipping weight was lighter and I kept one of the pairs, as a courtesy I refunded her the total amount (I tried to do a partial refund but accidentally refunded the whole amount) and sent her another invoice for a total of $30.50 for reduced amount. She tried to pay but she says it came thru saying $19.50 with a $36.00 fee. Should I cancel that invoice too and try resending another one?