Very sorry for that Tran. Because you already said it yourself about Throwing some Money... etc. next time maybe you can ask an adult to talk to them for you so they can negotiate, it is a big cost if the plants die, so a little bit of extra "effort" will make everyone happy. What I am sad though is that those people actually would do it to a young man like you... they don't even think to be ashamed of doing it to a young man and teach him the wrong ways of doing things
Very sorry again for your experience Tran.
Though Tran you should also have specifically told or mention here that the government agency that you are talking about is asking you "tell me that how to remove the pests and diseaser" Because removal or making sure that pests and diseases are removed is different from just having PRA document.
Next time if there is such a problem then please ask Supplier or maybe even pay the Plant protection guys for a Fugicide and Pesticide Dip. Which only involved dipping all the plants in a liquid with Fugicide and Pesticide for a bit of time and then that should be it!! Of course it will mean added cost but that should do the trick.
TTFN
Arvin