Opodo complaint: Ticket Booked but cannot use opodo cheated

I got diverted to Opodo by Skyscanner for my flight booking from Mumbai to Abu Dhabi.
I have been a customer of Sky Scanner since a Decade.
When i was booking the flight for Mumbai to Abu Dhabi on Opodo it showed me Via Doha transit to Abu Dhabi and i accepted to pay and booked it.
However when i booked the Flight i received shockingly 2 separate Tickets.
One is from Mumbai to Doha(Air India Express) and other one is Doha to Abu Dhabi(Etihad Airways) my Visit Visa is for UAE. It was shocking to me that i could not travel with this ticket coz they made 2 Separate tickets. I was not allowed to do OK TO BOARD.
Air India express Airline says according to the tickets I am going to Doha not Abu Dhabi hence they didn’t allow me to Board the flight.
On top of all this the baggage allowance for Air India express was 20KG and Etihad Airways was Zero KG.
How can a passenger travel on Via Flight 20Kg on 1Flight and zero Kg on other half.