My question is are there people who might be able to repair the disk? In case the motor itself has failed, for example. And if not, what sort of cost is it likely to be to attempt to recover it?
Yes there are people who can recover data.
How big is the disk ? Do you know what volume data you're after and it's location in the directory structure, or do you just want a general fishing expedition to catch as much as you can ?
Sending it somewhere decent and trustworthy you will be looking at a minimum sum in four figure denomination.
If it's a business drive, your business insurance
might cover the cost. But then they might not take to well to the idea that no attempt has been made to even do modest backups.
I apprecite that if the heads have crashed it may be impossible anyway.
Recoveries have been known from drives that have been wilfully put in a fire ... amongst other things.... so never say never until you've given it a go.