A Prank/Nuisance call at 1AM in the morning

Just as I was having a conference call with my 3 friends, I received this call. The caller ID that appeared on my phone was "Withheld" which basically means its a private number. Hence, I was hesitant to pick it up. Then, I answered the call. here is the dialogue.

*Cantonese*
guy: you selling this this this number on lowyat forum ar?
me: yea
guy: what price you selling?
me: you offer, I not sure. I dont ask for a high price
guy: you offer la
me: uh... how bout rm20-30 then? (bear in mind this was 2 numbers. Not one. Its not unreasonable at all)
*they were giggling over there (all guys btw)*

I then heard somebody on the background saying in Cantonese: "Go die la"
me: woa..so fierce meh. call me go die

Phone was passed to another guy. Since I am not good in Cantonese, I switched over to Chinese.
guy: you this type of number wan sell for so high price? Lanjiao ar...
me: if you dun like just skip my sales thread la.
guy: you better close the thread and stop selling. now!
me: yeah right, who do you think you are? you call me close, why should i listen to you?
guy: you better close I tell you. This kind of number also wanna sell online.

Then the guy was talking some crap about some stuff that was not important and I just hung up the phone. I was very pissed that time as it had totally spoil my mood. Then after pondering for a while, is it even WORTH me getting all hyped up about this type of anonymous prank calls? So then i continued chatting with my friends.