Several online platforms can facilitate the collection of excess sales tax. Here are some options:

Government Portals

1. Federal Board of Revenue (FBR) Pakistan: The FBR website allows businesses to register, file tax returns, and make payments online.
2. State Tax Authorities: Many state tax authorities, such as the Maharashtra Sales Tax Department, offer online platforms for tax registration, return filing, and payment.

Tax Compliance Platforms

1. Avalara: Avalara offers a suite of tax compliance solutions, including sales tax collection and remittance.
2. TaxJar: TaxJar provides automated sales tax collection, reporting, and filing for online businesses.
3. Vertex: Vertex offers cloud-based tax compliance solutions, including sales tax collection and remittance.

E-commerce Platforms

1. Shopify: Shopify offers a built-in sales tax collection feature, allowing merchants to collect and remit sales tax.
2. Amazon: Amazon provides a sales tax collection and remittance service for third-party sellers.
3. eBay: eBay offers a sales tax collection feature for sellers, with the option to remit taxes to the platform.

Accounting and ERP Software

1. QuickBooks: QuickBooks offers sales tax tracking and reporting features, allowing businesses to collect and remit sales tax.
2. Xero: Xero provides automated sales tax calculation and reporting, with the option to integrate with tax compliance platforms.
3. SAP: SAP offers a range of tax compliance solutions, including sales tax collection and remittance.

These online platforms can streamline the process of collecting excess sales tax, reducing errors and ensuring compliance with tax regulations.