A Jersey card shop owner, has said she is selling fewer large Christmas cards than usual because of size-based postage charges.
Alison Baker said this was because larger cards cost more to mail.
In 2010 Jersey Post brought in a system that meant the amount you paid to send letters and packages depended on their size as well as their weight.
Mrs Baker also said her shops had stopped selling stamps as varying postage costs made it too complicated.
She said it was very disappointing they could no longer offer a complete service.
Jersey Post said that 165 people in the island had to pay a surcharge in one day on over-sized Christmas cards.
Gary Carroll, Service Delivery Director of Jersey Post, said it was a small number of people.
He said: "Yesterday we handled about 150,000 items we delivered and only 165 people we had to surcharge, there are a number of people but it is a very small percentage of people.
"There are also people who post in the UK, it is not just local people who post, the Royal Mail will also surcharge for items that haven't been delivered properly."