Illegal plot proposed land lord against Rs 100000 my amount debited

I want your legal opinion on plot dispute. I will explain clearly. 1. On 15.12.2019, I given booking advance amount of RS 1 lakh check and booked plot no.165 in Urbanrise eternity, Chennai, alliance group. 2. After continuous discussion with Urbanrise team, on 17.12.2019 I know that this plot 165 was agreement done with other person all most three months back. Regarding I have mail communication from Urbanrise person Malik from official mail. 3. What they communicated during first day discussion, without my approval they won't deduct check amount. i clearly said if this dispute is not cleared by Saturday, I will come and collect check But suddenly on 21.12.2019 my amount debited without my permission. 4. Personally I went and discussed on 21st, what they said it their mistake, unknownly check deposited in bank and again they took time upto 23.12.2019, to get clearance on plot no 165 from other person. 5. On 23.12.2019, I received call from Urbanrise person Malik, and he is saying that we won't give re-fund where ever you can go and discuss. 6. I given complaint to next level and GM given mail to me saying that no dispute on plot no 165, go for further payment. But I know that it is not legally cleared from other person, why I am saying confidently, no legal clearance documents or no mail communication and also asked write up on letterhead they said it is not possible only mail communication is enough. 7. I personally sent WhatsApp message to GM, saying that I don't want this plot and refund my amount. He said he will refund and he asked cancellation request by mail. I sent mail. They said they will refund amount in 10 working days, now 10 working days over, still not refunded. I need your advice on this, I get your mail I will forward mail communications and supporting documents. Agreement done by other person on plot 165, same proposed to me, against my amount RS 100000 debited without my approval is a illegal.