I do not understand. Thunderbird client is free. You can download the free official version at thunderbird dot net

Hello David, the thing is that at April 2020 I agreed with some payment related to Thunderbird client preinstalled on my Ubuntu installation. Unfortunately I don't remember concrete agreement. I thought that it was payment for using those email client. After that the payment withdrawal were once per year. Also I'd like to note that I'd reinstalled Ubuntu on my laptop later and now there is another instance of the client. Let me provide the screen-shots of those withdrawals on my smartphone. Appreciate any advise how I can identify those payment agreement and how to terminate it (because currently I don't use it anymore). Thanks

Aha! Now I understand. You were paying for annual fee of the OWL addon that allows Thunderbird to interact with Microsoft Exchange email server. You can contact the OWL vendor to review your contract and cancel future payments by going to their website at https://www.beonex.com/owl/ Just to be clear: after canceling that contract, you need to go to the tools>addons section of Thunderbird and there you can uninstall the addon.

Owl is a TB add-on with a license fee. Contact them through their support email to cancel or modify the license. Otherwise, TB is free software, and the vast majority of add-ons are license-free.

Ok, I'll try. Thank you for your advise!