One suggestion: don’t use Twitter as your support/contact system. I don’t have an account with them, don’t want an account with them, and so it’s a turnoff to think I might not have a good way of providing feedback or get support if I paid for this product.
As long as there’s responsive support via standard ‘open’ channels such as email or phone, why would you care whether others can use other channels (e.g. regular mail, fax, or home visits :-) ) to get support?
‘Friendly’ how? I’m wondering how it’s better than a ticketing system or email.