I just spent 15 pounds on this and I wish they'd made it clear before I did that I won't be able to use the service because I have an old chromebook.
Please can someone give me on advice on how to get a refund?
If you had checked out the list of supported devices it does state that Chromebooks are not supported regardless of model or age.
Staff might take pity on you, but any chance of a refund you must go through live chat. Make sure you click “chat online” within the green box, don’t hit “get help quicker” as this is a bot.
Why didn’t you take the seven days free trial?
This allows you to sort out basic stuff, like is Now going to work the way you want it to work on the device(s) you want it to work on, before laying out any money?