First: I have never seen a legitimate RSI package offered for sale on EBay. 100% of those I have witnessed were pirate copies or activation-not-included offers of CD media.
That being said, there is a simple form to fill out to transfer software registration from one company to another.
Once the registration is in your company's name, your Tech Connect contract covers it.
If you have a support contract, RSI will reset a corrupted activation, ship you new activations, ship you new CD's, and allow you to download updates.
If you do not have a support contract, you are entitled to none of those services.