Not too sure what your question is really (probably why nobody else has replied either)
"Went to traffico 3 weeks ago to get everything cleared and nothing no answer. not getting anywhere." - To get what, exactly, "cleared"?
"How can I find out why my car is a problem at traffico?" - What do you mean by your car being "a problem" at Tráfico?
Are you saying you have never had a registration certificate for this car in your name? If so, I think perhaps this needed sorting before you decided to sell it! Assuming hte car is correctly registered to you, there should be no difficulty obtaiing a duplicate certificate from Tráfico (see here) If your Spanish is not adequate to deal with the jobsworths at Tráfico, your best bet is to employ a gestor to sort out whatever your problem with this car is, though.