Perpetual license

We installed perpetual licensed of Solid Works version 2014. We paid subscriptions for updates and assistance for 2015 and 2016. Then we discontinued the subscription. The laptop in which the software was originally installed had failed and the software was installed in another laptop in 2021. Proper approval was obtained from DS. Now we are accused usage of pirated software by lawyer firm on behalf of Solidworks. We are not provided information such as MAC address and IP address. We are 100% confident that we have not used pirated software on our local area network. We receive some files created by others outside our organization such as vendors and customers and we do further development on that and shared to vendor for manufacturing. Does this attract infringement? My Question: If the files created by our vendor/customer are out of a pirated software, are we punishable. In such case how to defend? Whether perpetual license is good with out annual subscription? They are insisting for "amicable settlement". How to come out of this issue?