Is that link to produce the captcha image correct? I'm thinking of the bit that says "charcators" where I'd have expected it to say "characters" or "charactors", and "verificiation_image". Might be nothing, of course whoever authored that function can use whatever parameter names they like, and I guess that bit wouldn't work at all if they were really incorrect.
Other than that, though, you have to balance out making it impossible for spammers but still usable for normal people. I have no contact details on my web site, just a form with a few boxes and a note that says "if you're offering to boost by web position, number of followers or size of anything, don't waste your time" and I still get people who spend time filling out the form and sending this junk in.
Also as the code isn't PHP, you might get a better response in a more appropriate section of the forum.