SOTC — demanding extra for mistakes made by them

Hi,
In March 2019 I got a written quote for a tour to Sweden for 3 persons to travel to Stockholm and proceed to Falun by train.
Your quote was for INR 323190/-
Including railway.
You confirmed all details and asked for payment and Rs. 255000/- was paid in March itself for the tour from 24 th June to 27th june.
In the first week of June they said they could not book the train tickets from Stockholm to Falun and we were asked to do it by ourselves.
We have booked railway at SEK 2010
Same class 2nd. Because you said you could not book the train from ARN to Falun
Then they said they have booked air ticket so that we arrive on the 25th of June. Instead of 24th. This was not acceptable.
So they rebooked so that our original date of arrival 24th was met
Now they are saying due to the fault of the booking team this happened and the tour cost is going up by 30000/-
They won't release the tickets and passport unless I pay the extra amount
Which arose due to their mistakes.
Please point out what was my fault.
Regards
Hari.n.m