Your company is service provider based outside the EU. It provides services to customers outside the EU. Its clients can use its services when they travel to other countries, including within the EU. Provided your company doesn't specifically target its services at individuals in the EU, it is not subject to the rules of the GDPR.
It's either "target", or it apples to all EU customers. "target" is far less of a problem for companies that don't consider their customers data to be important.
