What are consequences of not filing GST returns within due dates?

In case registered taxable person files return beyond due date, he will be required to pay late fees of Rs 100 for each day of delay, subject to a maximum of Rs 5,000

I am a trader selling my products through an e-commerce portal, having an annual turnover of less than Rs 1 crore. Am I eligible to claim the benefit of the composition scheme under the goods and services tax (GST) law?

The composition scheme can be opted for by specified categories of suppliers, based on a prescribed threshold. A trader supplying goods through an e-commerce website has been specifically restricted from opting for composition scheme. As you would be supplying your products through an e-commerce website, you will not be eligible. 

Is an input service distributor (ISD) separately required to be registered under