SINGAPORE - Owners of the recalled Samsung Galaxy Note7 in Singapore have been voicing their unhappiness on social media over the exchange programme.

Hundreds of irked customers posted their feedback and queries about the exchange programme on Samsung Singapore's Facebook page, especially when the website for customers to register for their phone replacement crashed due to high traffic on Friday (Sept 9).

Due to the volume of users, many were unable to log in to book an appointment slot. The online portal was up again by Friday night.

Samsung Singapore said it "worked around the clock to stabilise the website".

At about 3.30am on Saturday, there was a post on the Samsung Singapore Facebook page apologising for the malfunction.

"We are sorry for the delay in loading or accessing to our Galaxy Note7 exchange programme website earlier on due to high traffic volume. We have worked on improving the website and will be monitoring round the clock," it said.

However, the demand for home delivery of the phone seemed to outstrip the available slots, prompting more annoyed feedback from consumers.

"We would like to assure all Note7 customers that we will endeavour to accommodate all home delivery requests," Samsung said.

On Facebook, it responded to each customer in turn saying that they are working to increase the number of slots for home delivery.

"We are sorry that lapses in the exchange process may have left our customers frustrated and inconvenienced, and we will continue to fine-tune the process to ensure that all Note7 customers are able to exchange their current Note7 for a new one," a spokesman said.

Samsung's latest flagship phone, launched just three weeks ago, was recalled on Sept 2 after reports that handsets had exploded or caught fire during charging.

There have been no incidents in Singapore so far, but the South Korean electronics giant is replacing all sold phones worldwide.

Customers can book an appointment to exchange their phones until Sept 25. The exchange period is from Sept 16 to Oct 2.

They can swop the phone in person at the Suntec Singapore Convention & Exhibition Centre or get it delivered to their homes for free.

Customers can get help transferring their data to the new phone if they collect it in person, but the waiting time can take up to one hour, Samsung said on its website.

Note7 users here will not be able to opt for a refund or a phone of another model, options which have been offered in some countries. They will also not be able to choose a different colour for the replacement phone.

However, Samsung has said it will offer a token of appreciation for customers during the exchange.

In the interim, Samsung will loan out smartphones to affected users .

Samsung said it has received thousands of registrations in Singapore Saturday morning.