Skill lync - Refund for the course I didn t enrolled

I received marketing calls from skill lync non stop once I gave my details on a linkedIn advertisement. Finally they convinced me to take a course on Full stack web development. I agreed and payed the initial EMI of **** rupees. Since Im the only provider for my family, Im finding it difficult to pay **** rupees every month as EMI. So, I told my councillor 'Keerthiga' that I don't think I can continue with this. So I want to cancel my registration. I didn't got any logins or nor I submitted the details for loan processing. But now they are saying, the first amount that I paid is actually a pre book amount and it is a non refundable amount. Nobody, not even the counsilor or the mentor (her Manager, Akash) didn't told me this. I cannot accept these dumb company policies and move on with my loss. Its **** rupees loss. Im not a place to lose such a money. Im completely fine if they charge me for the processing fees. But I need a proper refund for the course.