Iberia and Matrix / Google Flights phone booking
I just found a route from OSL - LHR - MAD - OPO and return on ITA Matrix. First flight is operated by BA but has a IB flight number. The rest of the flight except the last from LHR to OSL is operated by IB. The last flight also has a BA number. I have tried to phone Iberia to book the ticket but they say it is not possible. I have tried HUACA 4 times with the same answer. They say call BA since first flight is with them. But the price on BA is much higher than if I would book with Iberia. But when I check online on Iberia.com, I get some flights there from OSL to OPO with IB flight number, but it is not the specific flights I want, so I want to book on phone.
This is first time I try to book with Iberia on phone, I always book with BA directly and I never have an issue with them. I did not get a good impression from this to be honest.
Is there something I am doing wrong here?