Help me get my computer number (read caption)

I'm struggling in the BVC section, first time I did it, they said I have uploaded my documents but my physical documents didn't reach their place (as you can see in the first pic) Then, I heard about DGCA notice about Digilocker BVC, I tried it but they rejected it saying I didn't submit my BVC What should I do now? I have to upload and speedpost my BVC right? But how to? How will DGCA know it's mine? Should I send the BVC to the address given in the email? Please give step by step guidance, as this is my last chance before complete rejection (then I'll have to wait a month again)