I have had similar issues with my last name in the past. Here's some of my experiences -

1. AI changed the name in my ticket without much fuss - https://www.flyertalk.com/forum/34213063-post23.html

2. My US visa had my name as First Name: Piper Last Name: atGates ofDawn (last name 2 words). But my renewed passport had my name as First Name: Piper & Last Name: atGatesofDawn (one word). I emailed the US consulate and they of course said "go get a new passport if you ever want to set foot in our country". I got a correction stamped on my passport and everything was just fine - in the US and everywhere else I applied for a new visa with my last name as "atGates ofDawn".