GraphicRiver Item Customisation

Hi all guys,
I am facing a situation where a client purchased an item and after that he/she’s asking for a paid product customisation, within Graphicriver obviously. He/she noticed a customised product button besides the product in the download section and he/she is asking if the customisation work will be done by me or by someone else? I repeat, I never experienced this kind of situation and, as an author, I don’t know what is the correct procedure to be used. Suggestions please? :slight_smile: Thanks
Riccardo