Your reply in the FAQ is:
Yes—SendFox is fully GDPR- and DPA-compliant and works for both B2B and B2C businesses worldwide.
- Data Processing Agreement - SendFox
- Privacy Policy - SendFox
- Terms of Service - SendFox

I am not able to find SendFox nor AppSump in the DPF register to confirm your compliance. Also, your DPA at https://sendfox.com/dpa does not clearly state any measures covering the EU-US Data Privacy Framework (DPF). This means you still rely on SCCs, so using your service in the EU does not protect against potentially costly warnings.
Please provide the required information (DPF register) and/or update your DPA to reflect compliance with the EU-US Data Privacy Framework. I really appreciate this because I love Sendfox and want to keep using it.