(2)Where the certificate of registration issued to a dealer is cancelled on the ground, that in the previous year his turnover of purchases or his turnover of sales did not exceed the relevant limit applicable to him under sub-section (4) of section 3 and the stock of goods held by him immediately before such cancellation includes taxable goods purchased by him on a certificate given under section 12, 13 or 49, there shall be levied on the purchase price of such goods a purchase tax which shall be calculated at the relevant rate of purchase tax applicable thereto under section 15 or under sub-section (3) of section 16, or as the case may be, under section 50:
