Ok. Have you tried a capture from VLC? 

 im trying m3u8 converter extension, should i use VLC instead? 

 Never used the extension. No idea how good it is, if at all. VLC can do a decent job. Video varies wildly, so there’s a ton of variables the influences chances of success with these tools unless they get deep into it (like the method I described, which is much more advanced). 

 Finally got a chance to look at it. 

Not a master manifest - just a plain one. You could grab all of the TS files referenced in it. 

Standard VOD, so no concern about a live window. No encryption, either. 

Worst-case, you could drop all of these files (in order) into any movie editor to stitch them together. 

There are other tools out there, but can’t vouch for them. VLC could do this in multiple ways. Here’s a CLI option: 

https://wiki.videolan.org/VLC_HowTo/Merge_videos_together/