• Failure or unable to make one plugin we cannot refund. because you can make many plugin or many other plugin variants, not for one type of plugin or one feature plugin
• You raise dispute to envato support, We will banned you purchase code because we don’t receive report from envato support.
• Violate Envato Rules so you get banned from Envato
• Sales Reversal, Refund or Issue with payment gateway
• Nulled user or associated with pirated programs especially items from envato
• Share/Sell your purchase code to others, this will cause your purchase code banned permanent

Yes, but you have to use a sandbox server. That means you work as a team. Please use Extended License.