Is this a new spa or a used one?
If New:
This spa DOES NOT have built in GFI protection. Check out your owners guide, or your pre delivery manual. It clearly states that this spa needs to be connected to a GFI Breaker.
If it is wired to a non GFI breaker, which is exactly what it sounds like, then you are taking a huge risk of electrocution.
You say you read in your manual that a GFI is needed. IF this is the case, then there is no GFI built into the spa. The manual wouldn't specify to provide a GFI breaker if there was one built in. No value what so ever in doubling up on GFI protection.
Don't use the spa until that issue is resolved.
Lecture Part II-
Are electrical permits required in your locale? Almost everywhere in the US they are, especiall for pool and spa wiring. I'd be willing to bet that this electrician didn't pull a permit, and didn't get his work inspected. There should be 2 inspections (usually). One is a rough in, where the wiring is checked before it is covered up. If that passes, a final inspection is needed to power up.
That's how it works in most places.
If permits are required, and one wasn't obtained, then I'd seriously question the credentials of this electrician.
Any moderately competent inspector would have caught the GFI issue on the rough in inspection. And a competent electrician would have known to put in a GFI breaker, or at least asked to see the wiring requirements. They do vary by spa brand.
Then I'd do some a*s whoopin at your dealer. If they told you wrong, they need to know it. And if it is true that your spa has no built in GFI, then I wonder how many dangerous installs they have out there.
Sorry for the long post, but this is potentially life threatining.