regn. for repacking goods

I have regn. with weight & measure act for importing material (mobile phones) and sales in India as it is. Sometimes we change packing boxes when it become in bad condition. Now, the dept. says that you should have also got regn. for packers under the same act. Could u please inform us about the legal postion of the same and also inform whether we shall take registration under excise/custom.

Thanks in advance.