How to approach of notice from commercial tax department, andhra pradesh

I got a urgent notice from Andhra pradesh commercial tax deparment, it consists of They informed that they are in arrears of tax to the department to the extent of Rs.49905 under VAT for the period jan, 2016. Inspite of several efforts of the deparment they have failed to make the payment and comply with the notices. They are hereby requested to make the payment of the above said arrears within 7 days of receipt of this notice failing which action will be initiated for recovery of tax under section 25 of apvat act 2005, section 9(II) of cst act 156 read with AP RR act 1864. We have no dues of tax amount and we have net credit balance in their DCB report. What to do ? How can reply to them. Kindly give suggestions