Relevant tax laws and regulations for collecting excess sales tax in Pakistan include:

– The Sales Tax Act, 1990: This act outlines the provisions for collecting excess sales tax, including the authority responsible for collection.
– Sales Tax Rules, 2006: These rules provide guidelines for the collection of sales tax, including the process for claiming refunds for excess tax paid.
– The Sales Tax Special Procedures Rules, 2007: These rules specify the procedures for collecting sales tax on natural gas, including compressed natural gas (CNG).

Additionally, the Federal Board of Revenue (FBR) provides guidance on the collection of excess sales tax through various circulars and notifications. It’s essential to consult with the FBR or a tax professional to ensure compliance with all relevant tax laws and regulations.