inner to outer cab corner gap

[MJN]

Had a shop install rockers and inner/outer cab corners for me. I got my cab back and the inner and outer corners have this rather large gap left. I'm looking for feedback on how to fix this, fill the gap. I understand the shop should've done this correctly, that was the whole intent of them doing this work and I will be addressing it with them but since I've already got the cab home I just am looking for thoughts on making this work and fixing it.