How to get what was promised?

Both my father and brother-in-law started working for Tracy Monks Construction in June ’07. When they started, they were union workers but the company decided soon after not to go through the union anymore, so they were given the option to stay with the company or go with the union. They chose to stay because they thought they would have decent insurance through the company. Unfortunately, they are getting the run around through both their employer and the insurance company about being officially signed on for this insurance. They have qualified and have been paying for this insurance since August but have not yet received a card or any form that will allow them to actually use it. TMC says that they have faxed the information to the insurance company; the insurance company says that they never got it. I need to know, what sort of options do my father and brother-in-law have at this point to get what they were promised and have paid for?