How can I fix or back up a system after I use gparted to resize my drive and the system will not start? I created an EFI to run Ubuntu on my mac it was working well but I didn't have enough space so I created a another partition in disk utility and then went to gparted and turned the new partition to un-allocated space, selected swapoff on my SwapSpace  partition in order to move the un-allocated space next to my ubuntu partion.
Now I can  no longer select  macOS to boot and am exclusively stuck in linux. I don't know to much about this stuff and am really struggling.
Apple support says to erase everything but I have no backups.
My whole drive for my mac is still there and I can see it is taking up space. I just cant access it 
Is there a way to salvage the system or at least back things up now that my system will not boot?
I was actually able to figure this out myself (no thanks to Apple), but have seen a lot of questions similar, so I thought I would share what worked for me:

I downloaded Gnome Disk for Linux
reformatted the corrupted drive to Apple AFPS
and then remounted the drive

I was able to get everything back and into macOS.