Maybe the person who was sent out was just a helper or apprentice with no license and no real experience.
There are two types of electrical licenses in New Jersey: an electrical journeyman license and an electrical contractor license.
New Jersey offers 2 different kinds of electrical certifications / licenses for electricians:
Qualified Journeyman License. This license allows you to work on wiring for heat, lighting, power sources, and other electrical systems without being shadowed by a licensed electrician. Plus, you’ll be allowed to train apprentices at your workplace. This license, however, does not allow you to apply for a business permit.
Electrical Contractor License. With this license, you can take on larger electrical contracts and apply for a business permit to become a small business owner. You’ll need to apply for the test before you’re even allowed to take it; then, you can receive your license after passing the test.
Did the person have a Qualified Journeyman License or an Electrical Contractor License?
How long did they have the license?
Did you verify the license?
I would get a new electrician who is qualified and competent to locate and fix the problem and not just assume that it is probably a defective pump with no basis for that assumption.
Maybe the grounds and neutrals are tied together?
Maybe there is no neutral and the ground is being used for a neutral?
In any case, I would get a qualified electrician who knows what they are doing to figure it out and fix it.