I was threatened by my freelancer that she will destroy my business (by destroying our SEO) if I don't give her a good feedback. So, she forced me to give her a good review despite I don't want to do it. Then she tells me she will give good review to me too, which in fact in the end she gave me such a terrible feedback. After giving the feedback to her, I got an answer from our marketer that such threat will be difficult to happens unless she pay 100x more than what I pays her weekly salary, despite she said that she doesn't care about my money as if that she is willing to pay 100x or more than her salary just to try destroy us.
What I don't think right about upwork is that : I reported to upwork by making a ticket to solve this issue, but somehow it took upwork 1-2 week before deleting eachother's feedback and closed the ticket as solved already as I suppose either it should be resolved after eachother's feedback is removed and or remove each other's feedback much quicker.
Because I want to become a loyal client of upwork and feel safe using it. So I have few advices.
My advice is, you will need to create a system that will not let this such things occur again. For example : You should let your IT developer to let me (Client) remove my own feedback.
The reasons are :
1. Some freelancers cheats just to fake reviews.
2. Some freelancers became rude, offensive, and or threatening after ending the contracts.
And some other reasons.
If you let me to able to change our own feedback, this might likely won't happens despite if it'll take 1-2 weeks till effective.
**Edited for Community Guidelines**
for the record, negative SEO doesn't work.
People mistake "penalty" with "natural" organic rank. What happens is they spam your site with a bunch of junk links, Google sees this as a signal and starts giving your site more attention in the SERPs. You see this as a positive thing in your analytics and see an increase in rank. Then, Google's algorithms catch up to the spam links and devalues/discounts them. Your rank drops to where it should be naturally without the links. You see this as a "penalty" but really it's just the algorithms catching up with the poor links and irgnoring them.
So, for the record, nobody can tank your site unless they have access to the local code.
I am sorry such an unfortunate situation happened to you and it took a while to resolve. Generally, Upwork can edit or remove feedback only if it violates ToS. That's what happened in your case and that's why feedback was removed. Since we intend to mantain integrity of feedback system such situations are reviewed against the ToS on case by case basis.