JustDial.com — deduction of extra amount over predefined monthly emi

Just dial is deducting extra amount from my account over predefined emis... We have tried contacting their executives for the same, but didn't get any satisfactory reply. Also, they don't reply to our mails which were sent to the mai ids given by their executives.
Also, they are not allowing us to contact the concerned persons over this subject.
Our three months emi calculates as inr 17, 700 while we have paid 5900 as cash, later on...5898 by card payment and further they deducted inr 10095 thus total actual deduction from just dial is 21993 over predefined amount of 17, 700. Thus, they have deducted extra amount of inr 4, 293.
Main headache is they don't give any proper mail id or contact person... To which we can make complaint about these issues and get the things sorted.