My Account Show usage over 5GB but there are very less emails in the inbox

My Account Show usage over 5GB but there are very less emails in the inbox

Hi Team,
    My account is getting continuosly blocked because it says I have crossed 5GB limit for my email address ( support@kangarupolymers.com). I have deleted everything from my account & only kept importatnt emails but still the space allocation shows the space has exceeded.

Can you please review my account & let me know what to do in order to see the free space.

Thanks
Varsha Shrivastav