Please be sure to check the contractors license number prior to signing a contract with any company. A good idea would be to get a comparable quote from a fiberglass company and one from a gunite builder in your area.
If you are referring to Universal Rock Pools license # 83199 out of San Bernardino their license according to the CSLB web site has been suspended. If you have a lien release from the plaster company you might try calling them directly to resolve the problem.