As title says, the description says you can use BBcodes but I tried both HTML and bbcodes and nothing worked, they're displayed as plain elements: <b> or [b] for example, so they're not rendered I guess.
This is working as intended. BBCode cannot be rendered inside [CHARGE] tags as this may alter the computed hash between the time of the message being posted (when BBCode is not rendered) and when the post is displayed (when BBCode is rendered).
I'm talking about the "Purchase" event, not the "Content" event. The Purchase event isn't related to the CHARGE bbcode, but to the ability to buy DBTech Credits with real money. Furthermore, your previous statement isn't correct, I can freely use BBCodes inside the CHARGE tags.