Sometimes banks charge hidden fees for transactions.
Cash advance fee
On rare occasions the amount you get charged may be higher than you expect. This is normally due to your bank or card issuer charging an additional Cash Advance Fee. This happens when your bank decides that your payment is a Cash Transaction. Xcoins does not have control over this charge. If this happens, you should contact your bank and ask them to refund the fee they charged you. This happens because Visa and Mastercard in Jan 2018 decided to consider all cryptocurrency transactions as cash (MCC 6051). You can read more about this here.
Be careful to avoid misunderstandings with your bank or they may accidently file a payment dispute, which, if not managed properly could damage your credit rating.
Exchange rate fee
Exchange rate fees are a lot easier to understand. Whenever money is exchanged by a bank from one currency to another, the bank takes a cut via a fee. If you hold money in Euros, make sure to purchase from Xcoins in Euros, and visa versa for Dollars (USD).