Guarented Rentals Complaints & Reviews

I have ordered on 19th May 2020 one wooden study table and a chair(Order #31061) for which i have paid 750 INR to them at the time of placing the order and rest once they deliver the product. They commited to have it delivered on 21st May 2020. However, when I enquired on 21st May after having no communication, through their customer service # [protected], they don't pick the call in first place. After several trial, they communicated that its not in the inventory currently so cannot deliver. Therefore, i asked for refund and they replied that managment will call you back and they are not ready to refund the amount as well. They cheated entirely.
Kindly assist me further. Moreover, they are extening days in their website for delivering the service by one day everytime after the call.

Payment id: [protected]
Amount : Rs Rs 750
Payment date: 19 May 2020

Its been more than a month that i am asking for rent to own details for the products that i took on rent in 2017 and i am not getting proper response from them.
On the other hand they are continuously calling me and sending mails to pay the rent of those products.
Also in october 2018 i asked for rent to own/purchase price of the products and i got the amount as lumpsum 4000, now in april 2019 they sent me the purchase price as 11000.
I am continuously paying rent from last 2 years and it should decrease the purchase price logically, but from october to april it has increased.
Is it possible? Are they deducting or adding my paid rent to their purchase price.