Coutloot — Company not paying me the money I received

Hi

Coutloot is an app that allows people to sell thier used clothes/accessories/electronics
I have sold 4-6 items till date, but my last item (a dress) was sold for 430/- rs and the company is refusing to pay me that money saying that i need to "register for GST" to be able to receive that money.
1. If the app is for selling used products then how can someone have GST?
2. If GST is mandatory why did they not tell me before i sold it.

I am constantly texting all of thier executives but they are just saying :money will be transfered soon."
no one is giving me a date
this has been going on since 6/01/2022

kindly help in either
1. Getting my money (rs 430/-)
or
2. Ask the company to return the dress i sold.
I cannot be the one at loss here.