From what you have written, the change in company name and tax identification number seems to be a ruse by the prior company to get out of a valid debt owed by you since it did not file for bankruptcy protection nor dissolved.From what you have written, I would sue both companies for the $1,500 back claiming that for all intents and purposes the two companies are really the one and same entity and the changes recently made were done to defraud creditors like you.