🇳🇱Netherlands @Eric Wassink - Qumup

For Drupal 10 websites using Symfony 6, there are indeed some more issues with this module (2.2.0). These can be resolved by modifying two files, as shown in the attached patch.

I haven't tested whether these modifications are also necessary for Drupal 9 websites. In the current version of the module, incomplete payments (and probably complete payments also) result in a fatal error. After applying the patch, it works seamlessly under Drupal 10.2.1.