Your dad (or the construction business if it is a separate entity, such as a corporation) can sue Sprint BUT I think that if you look at the agreement with Sprint you will find that it contains a clause which limits the damages which you can recover to a minimal amount. Depending on the circumstances, this clause may not be enforceable (for example, if you can prove that Sprint deliberately gave away the number knowing that it belonged to your father and that he was fully paid), but it presents a major hurdle to any successful law suit. Also, the main damages you would seek to recover are called consequential damages, that is damages which are not directly attributable to the wrong. For example, if I fail to pay you $100 due under a contract by which you sold me a bicycle, the $100 you didn't receive is direct damages, and can clearly be recovered. The rules are more murky with consequential damages, for example if you claim that because I didn't pay you the $100 you were unable to buy some stock you had planned to buy which tripled in value the next day. You are claiming that because Sprint gave away the phone number, your dad lost business, which is consequential damages. The general rule is that consequential damages can't be recovered for breach of contract unless the possibility of those damages occurring in the event of a breach was within the contemplation of the parties at the time of contract. Also, the damages must be proximately caused by the breach and not too remote. For example, the claim that you would have made a fortune on stock if only I had paid you the $100 I owed you would not stand up, both because losing money on a stock deal would not have been the type of damages which would have been within the contemplation of the parties at the time they contracted, and because the loss is pretty remote from the breach. A consequential damages claim which might fly would be something like a claim against an alarm company that, because it breached its agreement to monitor your home, the contents of your home were stolen resulting in thousands of dollars of loss. That is why alarm companies (and I bet Sprint as well) always have clauses in their standard agreements which limit their liability for consequential damages.