You have been in touch after we highlighted the case of a viewer who was hit by an unexpected cash advance fee when he used the online payment service Nochex.
Ronald Feltham found a cash advance fee added onto his statement because he had used a credit card.
No warning was given on the e-money service website at the time of the purchase that an extra charge could be incurred.
A cash advance fee is usually levied when a credit card is used to withdraw money, for online gambling or to buy vouchers.
Customers are charged this type of fee depending on the code online payment companies have agreed with their bank.
Viewer David Waterfields has contacted the programme to say he was stung with a £3 charge for using his MBNA credit card on a Nochex transaction - as was John Ballinger.
Rob Scarisbrick from Liverpool also says he was charged when he bought a laptop and paid through Nochex.
When he disputed it, the e-money service sent him this reply.
"Our transactions are coded when they are processed, the codes we must use are stipulated by Visa and Mastercard. Unfortunately Mastercard have decided to code all our transactions as cash advance transactions, therefore leaving some customers with cash advance fees.
"We feel the code Mastercard are issuing on our transaction is totally incorrect and are in ongoing discussions to have it changed. We cannot however tell you when or if this change will take effect."
Mastercard have denied they set the codes, which they say are set by Nochex and its bank.
Nochex, it seems, has had issues with its bank when it comes to flagging up credit card payments as cash advance transactions - and they claim to have no say about which code is used.
More banks are starting to take advantage of the fact that theses transactions are being coded as cash advances.
Natwest, for instance, have written to viewer Heulwen Egerton to make her aware of some changes.
"I found that they were changing their definitions of cash advances, and that they were including in their definition of an electronic money transfer, a card transaction over the internet."
Natwest have confirmed they are introducing new charges for specific situations.
Nochex claim to have no say about which code they use
"Where the merchant's acquiring code allows us to identify them as providing one of these cash equivalent services, the transaction will be treated as a cash advance," the bank said in a statement.
This means that from 1 May a transaction made through Nochex with a Natwest credit card will be treated as a cash advance.
However, customers using a Natwest credit card on Paypal will not be charged a fee as the bank has decided to exclude it from the charges.