I am a writer by trade; I ghost blog, write web content, articles etc. I am not in the SEO business and have ended up learning more than my share.
I bought a few services like this, most recently I bought a "1000 forum backlink with 500 bonus" package from a seller that had about 100 positive reviews and not one negative review. Of course I thought "this guy must be great" however, it's been nothing but a headache. He ended up sending me a report for 1043 forum backlinks and as I looked through them, I noticed that he was recycling and re-using forums. There weren't 1043 unique websites as he advertised and they were very low quality, garbage sites. He registered for dozens of user accounts for each forum (a huge no-no that will get me flagged" and then inserted my url into the profile page under "website". It wasn't in a thread as I thought (but that wasn't even an issue), nor was it in the signature (still not important).
Not one of those 1043 links were related to my niche at all (as advertised in his ad). The sites were all over the place and not one was related to my niche. WHICH, as we all know, makes them garbage links and it doesn't matter how natural he says they were, because they're not niche related, google will figure it out and either flag my site or penalize me. I complained to him and his reply was "you can remove your review and I will refund you" and my reply was "remove my site from those forums and I will remove my negative review". He instead tried to bully me into removing my review.
He thinks he can bully me into removing my review and I wonder how many times he has done this. The other two sellers pulled the same thing. "Oh you're going to ruin my business on fiverr, I'm so sorry, please remove the neg review" and both times I did, this time, I was livid. I learned my lesson, I'm never buying a service like this again. Fiverr will see my url and his report and they will see that he's selling black hat garbage.
My advice to you folks is to check your reports. And don't be bullied into removing a negative review because you're not helping the rest of us by doing a poor seller any favors. Don't use forums to spam, make the effort to interact with the community and build up your profile, use them to your advantage and never to the detriment of the forum.