Since that we should be the sellers and since the buyer name (or company name) appears in the invoice, are we allowed to get in touch with buyer?
Try to search them on google, i think you will find contact methods (fb, twitter, etc).
Of course! But is there some problem from Envato side?
I think not, it’s just an aethical issue depending on importance of what you want to say.
If contact is really hardly needed so why not to.
At least I’ve never seen any rules forbidding this.
Are we not the sellers