First, a BIG thanks for your donation. The continued growth of Thunderbird is directly due to donations such as yours. I regret there may have been issues on your donation. The place to pursue this is at this address: https://www.thunderbird.net/en-US/donate/help/ Again, you have our thanks.

on https://www.thunderbird.net/donate/

Are there additional fees on my donation? We do not collect any additional fees or taxes. When you donate in your local currency you are not charged a conversion fee by your credit card. Optionally, you can choose to cover our transaction costs on your donation. This is completely voluntary and you may opt in or out using the checkbox on our donation form. Our organization is based in the United States. We encourage donors to research any additional external taxes or fees that may be applied by regulators such as your bank or tax authority.

What are your transaction costs on donations? When you opt to cover our transaction costs, you're covering both our processing and donation platform costs. The costs associated with our robust online donation system allows us to continue scaling sustainably as our supporter-base grows. Our donation platform and payment processor partners reduce internal costs associated with maintaining our own system from scratch. Our partners ensure we can accept a wide range of currencies/payment methods and remain PCI compliant in all of the countries that we accept gifts from. The transaction costs donors may choose to cover are based on an estimate of our overall costs. Due to many factors actual costs may fluctuate.