I believe you should have two installs with each purchase, so it sounds like they're both used up (maybe through a reinstall?). Assuming this is a PC license (as opposed to Mac) I would contact elicense directly at:
support@elicense.com (you will need your order ID to be included in the email)
If it's a Mac purchase, you want to contact PISD:
peds@pisd.co.uk (you will need your license key to be included in the email)
Issues such as yours are usually taken care of pretty quickly.