You can Claim TDS at the time of filing annual Income tax return, at that time what ever tax is liable on you based on your sale.For Example: Your Annual Sale: 10 Lakh, you assume 10% profift, so your taxable income would be 1 Lakh, and upto 7 lakh ther is no income tax liability, so in this case , you will get full refund of TDS deduct by amazon.For your further information you need to claim TCS also by filing TCS credit return in GST