I looked in to both websites and it looks like that you have both DA and PA higher than yours but there are few areas where they are beating you!
- URL structure
They have a better URL structure that discusses the page right after the domain where as your domain structure contains a directory between the page and the domain.
- Content
Their content is more strong and stable as compare to yours plus the use of keyword is to the point. Try to redevelop your content and make it more stable and user friendly.
- Overall on-page
Try to audit your complete website and see what other stuff are need to get done in order to make a website more user friendly to users.
- Links
I do understand that your competitor does not contain good links but if you try and get some relevant links that talks about you, you probably will easily out rank your competitor.
Hope this helps!