our reseller/payment provider upclick should be able to help you out with this, try the transaction finder on www.upclk.com or contact their support if the transaction finder doesn’t help. We only store the actual license keys ourselves with no possbility of connecting them to individual users data, which is exclusively stored with upclick for privacy reasons.
The create module itself however has always been free, so you must have purchased one (or more) of the other modules. Please keep in mind the modules will only work for the main version they were purchased for, so if you purchased some modules for e.g. PDF Architect 4, you can use them in PDF Architect 4.1 but won’t be able to use them anymore in PDF Architect 5.