There is nothing free in this world. The deposit of Rs 4500 includes cost of both
ONT and STB. As there is no sale, taxes are saved by the company and being the property of the service provider, he is entitled to claim benefits on account of depreciation year after year.
Further, the value of your deposit will increase with time (interest component) and the value of equipment in your custody will reduce with time on two counts, firstly by depreciation and secondly by the fact that replacement cost of any electronic equipment will decease over time.
You will take good care of his equipment, otherwise, you may not get refund of your deposit. He will invest your money in
business without allotment of shares, so no participation in profits, but when the whole business is at loss, you risk the delayed or even no return of your deposit.
So ONT and STB is free to you or your money is free to him?