Pulmo Oxycare Systems - Company not returning advance caution deposit

I took a medical device (BiPAP machine) for one month rent from Pulmo Oxycare Systems on **-**-****. An advance of total Rs **,*** out of which Rs **,*** was a fully refundable security deposit and a non refundable one month rent of Rs **** was paid in advance. My return date was due on **-**-****, which was Sunday and **-**-**** was Gandhi Jayanti. When I tried to return the product on **-**-****, the owner told that he will charge a additional full month rent.
The shop owner didnt mentioned the rule that if the return is delayed then refund will not be given earlier either orally or in any written form.
The snapshot of the Delivery Challan is attached.