Hello @StefanL38 

Chat is live from 09:30 - 17:00 hrs (Monday - Sunday) on BST at the moment. 
You tried at 9:45 UTC, which was 08:45 BST.

Update: Web chat is usually available Monday - Friday (from 09:30 - 17:00 GMT/BST) and Saturday - Sunday (from 11:00 - 17:00 GMT/BST).
But there are times we're unable to guarantee support this way - temporarily. You can speak to one of our support representatives via Webchat through our help center

Well maybe there are more meanings than one for “BST” what I have found with googling is

BST British Summer Time

google found this converter

Which would mean Add one hour to UTC to get BST

You said

You tried at 9:45 UTC, which was 08:45 BST.

The converter above says

You tried at 9:45 UTC, which was 10:45 BST.

@ the website-development-Team of deezer

simply evaluate the country you web-request is coming from and insert the correct local time

with mentioning the IP-adress location. 

If somebody uses a VPN which is located half around the globe to the real location of this user

mentioning the IP-Adress-location will tell the user what info was used to determine his local time

best regard Stefan

@StefanL38 You are completely right, apologies for the misunderstanding.

The problem was that you tried to contact us via webchat before the available hours since on weekends chat is available from 11:00 - 17:00 and you’ll get the chatbot help outside these hours. (9:45 UTC = 10:45 BST)
Thanks