Documents to be submitted to icai to attend gmcs classes.

I dont think any documents are required to submit at the time of registering for GMCS. You must submit Student Regn Number.

We are required to submit the articleship registration acknowledgement letter or the verified copy of form 103 as a proof of joining audit firm as articled assistant to attend the class. But I haven't received any of the two from ICAI. So are there any other documents that can be submitted in lieu of those two documents? 

You can submit a copy of Form submitted to ICAI along with postal receipt, if available.

Or

Mail to e-sahaayaata requesting them to send mail confirmation that your application is with them and is under process.