Your last issue raised on this forum was in 2017 https://support.mozilla.org/en-US/questions/1163738 So are you reporting an issue you want help with, or are you wanting to talk with Mozilla customer care. If it is the previous, we know exactly what it is you tell us. So error messages and other relevant things like how many Comcast accounts you have in Thunderbird will help a lot. Until you offer more information, the best any one can do is guess. If you are wanting to contact customer care, there is link [https://www.thunderbird.net/en-US/donate/help/ here ]that will allow you to send them an email, although from reading the page it looks like there is a donor portal you have access to to cancel recurring payments.