There are two things which make this very suspicious, like every other person who thinks they can get away doing this:
1) Why are you selling this method?
If it as easy as you claim it is, and someone else could make $600-$3000 a month, you could just make another account and another blog and make double the amount. Or triple the amount. Heck, why not make 10k a month instead of selling the method to 5 people who make 2k a month?
It seems like you're spending hours on this thread + planning to give help in PMs after people buy it. For $100. If your guide actually makes you that much money, then this is in no way an efficient use of your time. Heck, you're likely making like $10-20 per hour per sale, and that should be utterly useless compared to your earnings,
if they are legit.The only explanation I can see is that the part you quickly mentioned here:
a Facebook page with a follower base.
is much much much harder than you make it seem, making it impossible for you to earn more, and hence you resort to selling.
2) The vouch you have is utterly useless
There's one part of the vouch which makes it very dubious:
As to the effectiveness of the guide, it's hard for me to say as, again, I am not familiar with this method, nor the aspect of Facebook that was used. I also have not completed the method myself so actual payment proofs aren't available, from my side. However, from what WC has described to me and what I understand from the method, it checks out and I don't see why it wouldn't work.
The person vouching for you hasn't earned any money from it!
They just think it might work. It might just end up being something that doesn't work well, or needs a huge follower base to work, or something like that. Even if you prove payments, you might have the perfect setup to make it work, and your guide may not help others enough.
TL;DR: If this method was making OP any amount of money, and could be easily replicated with his knowledge, he would just need to make more accounts and repeat the process instead of selling this guide. The fact that he is selling this guide means that either this method cannot be repeated easily, or that he is fabricating everything. The vouch is useless too, since it has no proof of earnings, meaning that it does not show whether it can be replicated either. 
