It has given you a quite powerful lever against unsubstantiated paymant demands. It happens quite often that company A has a (debatable) claim to person B but e

It has given you a quite powerful lever against unsubstantiated paymant demands. It happens quite often that company A has a (debatable) claim to person B but ends up demanding money from person C. Happened to me once because B used my address and twice because A thought we had a contract, which we did not. In each case, A had no legitimate reason to store or process my data. In particular the GDPR forbids them explicitly to exchange C's data with any third party. Doing so could lead to severe penalties. In all three cases I only had to point out these facts once to stop the whole claim. Very comfortable.