Major retailers have stopped or paused deliveries to Northern Ireland due to uncertainty around post-Brexit customs checks.
Since the new year, consumers have been left frustrated by a lack of clarity over online retail.
Some major companies have paused online orders to customers in the north while they adjust to the Northern Ireland Protocol - a part of the Brexit agreement which effectively keeps the north in the European Union's single market for goods.
Other companies, including furniture retailers Made and Habitat, have stopped deliveries altogether.
Many customers have faced delays in receiving goods bought online, while some have had their orders cancelled.
Companies do not have to complete new post-Brexit customs processes for three months, after a grace period was introduced.
However, serious concerns have been raised that some companies will stop deliveries after the three-month period is up.
Many deliveries have also been hit by the ongoing coronavirus pandemic with reports of empty supermarket shelves on many products.
Many consumers in the Republic and other EU countries have also been hit by import duties and VAT on some goods they have bought online from the UK.
Here are some of the major companies affected:
Amazon: The retail giant has said that some items might not be available to customers in the north. It has also said that "some deliveries may take slightly longer than usual".
Debenhams: The company, which is in administration, states on its website: "Unfortunately we are temporarily unable to deliver any orders placed on Debenhams.com to Northern Ireland."
Decathlon: According to a message on its website, the retailer states: "We are no longer able to deliver any more purchases to Northern Ireland for the moment".
Dunelm: The company has paused deliveries. A message on its website reads: "Our home delivery service to Northern Ireland is temporarily paused while our teams make some technical changes to ensure our service complies with new requirements. We are aiming to have home delivery in Northern Ireland available from the 11th January, and are doing everything we can to potentially bring this forward."
Feelunique: The online beauty and cosmetics retailer has warned customers of delays in shipping orders, although this is due to the coronavirus pandemic.
Habitat: The furniture and homeware retailer has stopped deliveries to the north. "Sorry, but we do not deliver to Guernsey, Ireland and Northern Ireland", a message on its website states.
John Lewis: The retailer "temporarily paused deliveries and collections in Northern Ireland from December 30 while we awaited further guidance on the new trading arrangements". It said it aims to resume its services as soon as possible.
M&S: The company is still delivering but some customers have experienced delays in receiving their orders.
Natural Instinct: The pet food company has stopped deliveries to Northern Ireland. A message on its website reads: "In view of the guidance we are receiving regarding Brexit, unfortunately we can no longer ship to customers in Northern Ireland. We sincerely apologise for any inconvenience and disappointment caused but matters are beyond our control."
Next: While the company is still delivering, some customers have experienced delays.
TK Maxx: The retailer has told customers: "Please note, we’re temporarily unable to ship orders to Northern Ireland. If you have placed an order that ships to Northern Ireland, your order has been cancelled and you have not been charged. We apologise for any inconvenience caused and hope to be back very soon."
Zalando: Clothes retailer Zalando has warned that "due to Brexit, we are facing some longer than usual delivery times".
shopDisney UK: The company's website states: "Please note, we are currently unable to ship to Northern Ireland and apologise for any disappointment this may cause."
Halfords: Customers cannot order items for home delivery. A message on the company's website says: "This is a temporary solution, and we are working hard with our partners to ensure delivery services will be undisrupted post January." Halfords is an essential retailer and click and collect is still available.
Made.com: The furniture retailer said last month it would no longer be shipping items to Northern Ireland.
Tredz: A message on the online bike company's website states: "We no longer deliver to NI."
The Wine Society: The wine merchant told customers that "owing to the terms of the Brexit Withdrawal Agreement, like other wine merchants, we are currently unable to deliver either to members' addresses or our collection point in Newry". The company said it hopes to "resume deliveries as soon as we possibly can".