Om Sweets — deduction of extra gst tax on food item

Address: Gurgaon, Haryana, 122018

Website: www.omsweets.in

I placed an order of fried dhokla and 5 grilled sandwiches.
Which cost me :
Grilled sandwich 400
Fried dhokla 200
And over this they put the tax cgst 2.5% sgst 2.5% & cgst 6% cgst 6%.
Total of 17% tax, whereas it should be only 5% tax.

When i complained at there center to mr. Vikash with mobile no ([protected]), he gave such an un acceptable statement that we put extra tax on fried dhokla ie 12% but for plain dhokla it is 5%.
Is it that. Does it mean a shirt from addidas brand will have different tax from a trousers from the same brand.
When i insisted him to revert the charges he said "you can complaint against us but we will not revert it".

I have also taken pictures of the other bills (With delivery boy), all were having 5% taxes on it only.