Hi VTMOZ
First of all, remember that the MOZ scores are not used by Google.
All MOZ scores from SPAM score, to PA and DA are arbitrary scores used by MOZ to allow you to compare your website to other websites. Even then they are really only useful when comparing against websites in the same niche.
Yes the scores given by MOZ are useful as a measure to see progress, but I repeat they are not used by Google.
If you have a number of bad backlinks and you think that Google is penalising your rankings because of these links then feel free to disavow them. I would suggest that you make sure you are only going to disavow bad links though.
Again keep in mind that Google seems to be getting better at realising links from certain types of sites are Spammy and ignoring them.
When building backlinks you should always use a natural approach that means your site will gain and lose backlinks at a sustainable rate and you should never pay for backlinks.
I hope this helps
Steve