Im planning to buy Adobe Flash Builder.
But Im seeing that it lacks totally in support and stuff.
Is there anywhere else to get support?
Enterprise Support can definitely help you for any installation related issues as a free support. For any other technical feature or configuration related issue you would need to buy a support plan [may be per incident or any other plan]. Details about various plan offerings are here and contact information can be found here.: http://www.adobe.com/aboutadobe/contact.html
Also, for Flash Builder there's a very good documentation base here : http://www.adobe.com/devnet/flash-builder/documentation.html
This should help you but in case you have any query please at above mentioned numbers and concerned team be able to help you out. In case the question needs support plan they would let you know accordingly.
Hope this helps.