After 6 months your stamp fee doubles and they may ask for proof of how you are supporting yourself financially. You can avoid this by leaving the country and starting the process all over again.
If you tell them you are working online (although I don't know to what extent), I think you may run into some issues as Belize is your primary residence(?) and you are earning your money while here. GOB may want their cut of business tax, income tax, but since you do not have a work permit, you can't pay it. You may want to inquire with the immigration department. Just my thoughts.