Thunderbird doesn't have 'Customer Support'. It as open source and donation funded email program. The Community Forum is a group of people who come by and offer advice to people needing help. It's not a good idea to publicise your phone number as just about anyone could ring you and pretend to be someone they're not, even try to get money from you when they're not entitled to it.

The way forward is to post your problem and one of the contributors will, hopefully, respond to your query.