If unit has stopped cooling completely, meaning fridge only sits at 'room temperature' then you need to check these main things.
1. Inner fan still going?
2. Bottom fan and compressor still going?
*If all above going and unit has no cooling then unit has gas problem. Tech required. Fill out form at this link to get service, whether you are in or our of warranty.

https://www.bar-fridges-australia.com.au/making-a-warranty-claim.html

If you know part you need, see following;
Inner fan part number is BR125-FAN-INNER, $119, contact below to arrange
Under fan part number is BR125-FAN-UNDER, $89, contact below to arrange
Compressor, part number BR125-COMPRESSOR, price is $239, contact below to arrange