Cars24 Services — no transparency in rto charges

Address:

chennai, Chennai, Tamil Nadu, 600094

I opted for finance through cars24 for 1.6 lakhs. The amount credited to seller was only 1.51 lakhs. An amount of 5000 was charged by cars 24 with the following breakup. Rto charges - rs 3500, hypothecation charges - rs 1500.
About rto charges, before buying the car i was told that the rto charges would be extra and that would cost rs 2000. But now they have charged rs 3500. This is totally unacceptable.in addition, i am charged rs 1500 as hypothecation charges. This, i was not at all informed about. This is totally unprofessional service to deduct the amount right at the end without prior information. I want clarity on why the rto charges are being changed and not given receipt for and why i was not informed about the hypothecation charge before.