Left without a flight after being misadvised

Okay, so myself and my boyfriend are completely distraught over this whole situation...

My boyfriend was due to come to Cape Town from Croatia on Wednesday. When originally confirming our flight, I called the airport on my side (Cape Town) to see if he needed any documentation other than his PCR test to get into the country. They said no, he is european and will not need a visa.

When arriving at the airport (Split) in Croatia on Wednesday, they turned him away because he did not have a visa... which we had no idea he needed.

We have been on the phone the entire week on both sides, trying to see what the airline can do to accommodate this; even to only allow us to keep the return flight, but no, they decided to class the flight as cancelled...

We paid so much money for this flight after saving for months, I honestly don't know what to do because I can't get hold of anyone who can help me.

My boyfriend calls the airline in Croatia and they say we can have a 30 euro voucher.. HA! We paid 700 euros for this flight and they are offering a 30 euro voucher? I am completely heart broken - i haven't seen this man since December and now we are left here waiting again.

We also can't get his visa sorted without the details of the return flight so again are left in the dust.

I have been in tears and out of sorts since Wednesday morning and am left here feeling completely neglected by the airline as someone actually said to me on the phone that no visa was necessary - either they didn't check properly, or don't know their facts.

Please if anyone has any advise on the next steps we should take... I am open to anything.