Windlass Homes Projects Private Limited - I have booked flat in Alaknanda 6 unit No 503 at windlass River valley kunawala dehradun in August 2

I have booked flat in Alaknanda -* unit No. *** at windlass River valley, kunawala, dehradun in August **** and earlier **% of the total amount I had already paid including GST but now builders sent me demand letter regularly exclude **% GST. I have sent mail many times regarding GST and Input Tax Credit on construction service to windlass developers pvt.
Presently not got any satisfactory respone fm builders amd total amout is very change because **% GST excluding on balance amount (appx variation of * lac) that is the off beam way to harassing the customer.
Loan of remaining amount (**%) has already sanctioned by SBI i.r.t me but not disbursed due to variation in amount and presently expired due to not getting correct demand/response i.e the gaffe of Windlass River Valley.
I hv contacted many time via call/mail to yr CRM/staff and not got any satisfactory response and I have also clearly mentioned in my earlier mail about including GST in remaining amount to builder .
GST on balance amount which is not a good way to taking profits fm customer weather GST/Input Tax Credit on construction is a service matter of builders. Builder also getting waiver in GST from Govt.