C form & vat query

I m working in a import company where different type of product are being imported lyk machine and medicines. As machine 12.5% vat is being charges and for medicine its 5% also if C form is issued than 2% is being charges. My first query if we dont get c form from one company and we got blank c form from another company can it be adjusted with each other. Second query is it possible to see machine bt to show it as medicine and pay 5% Vat to government jst to avoid tax.