Mytrip.com complaint: Fare difference changed from 410 pounds to 930 pounds within 10 minutes

I am Punitha devendiran. I was calling customer care continuously for 10 days to rearrange my brother’s ticket. His ticket’s reference number QPJYZA. Every time I call, the result from the travel agent is ‘There are no flights in economy today’. This was incredibly frustrating.
The reason why I needed to reschedule the ticket is the fact that my brother desperately needs to return to the UK for work due to Brexit. I spoke with customer care. The first time I called, they told me that would call me back as soon as they had checked the fares.
Before writing this complaint, I spoke with one of customer care representatives(lady) . She answered my question very politely and said that future dated tickets can’t be rescheduled. Speak with Air India to reschedule the flight.
She gave me Air India number to call as well. I spoke with Air India , they said that they have informed that there were plenty of tickets in economy and business class.
Again I called customer service, explained everything about tomorrow flight (17th Jan) availability, he said that can’t rescheduled. Then I request him to speak with his supervisor. Then he ed me tomorrow flight with 468 euros equivalent to 410 pounds. I am happy to pay that amount and the call was disconnected.
Within 5 mins again I called, it came with 815 fare difference. Then I was asking him, will you accept it as a customer. I can’t accept this amount, within 2 mins again changed to 930 pounds, sorry I checked in the different site.