what have you done now!! Dude this is not a hilux, can't just bolt on a new gearbox!
Try autoprecision maybe they can cut you some new gears.
Otherwise your best option is to order parts off motocrosscenter they deliver to your eswatini PO box and sometimes SRA don't know about it, but if they do go and argue it because you only need to pay VAT on it, no import duties