Firstly thank you for supporting the PayClip!
As PayClip works a bit differently to other devices, it depends on an email address rather than, more traditionally, a terminal ID number. This means that once you have registered an email against a business entity, it is then linked to all of the financial transactions and history of this entity. Sorry to say, that this also means that when a business entity is closed, and the corresponding PayClip Merchant Facility is also closed, we are not able to use the same email address for any new entity.
I can let you know that we have received feedback in relation to this and have taken this on board - I expect that in the near future there will be some enhancements that will eliminate this frustration.
I hope that the above does explain why we currently can not use a duplicate email across different PayClip Merchant facilities.
P.S. Some businesses get around this by simply creating a new email for PayClip, by using a free email provider.