The really big bookmakers have a lot of customers. I don't think they are easily steered by the fact that they have a problem with a customer. After all, every bookmaker or casino has a problem with a customer, often related to payout of course. But it's true, a reputation can be destroyed in moments.
You underestimate the power of negative reviews. Every good businessman should care about EACH customer to maintain a good reputation and be ahead of constantly emerging competitors. Imagine, a certain online casino has 100 positive reviews and no negatives, that gives them, say 5/5 stars. At this point there's nothing that can stop potential customers from using this casino. Then, one day, a very bad review appears, which tells a horrible story where someone won $5k at the casino and couldn't withdraw the win. People will pay attention even to that one single neg, despite all the positives. As a result, due to mistreating just one customer a casino can lose many potential ones. At the same time, the other casino which has no negative (or less, because none is, probably, impossible) will win over the customers.
But there are negative reviews which are false or totally a lie which would be possibly made by competitors and we should really be watchful with that but somewhat people or the community isnt really blind on believing on this which doesnt have sufficient proof which it wouldnt really be that effective if they are trying to ruin out someones business or their competitor in the market.Reputation is something that can be build overnight.
This is something that you should protect as an owner since building it does cost all efforts or hardwork to gain that trust this is why you should really be mindful about on things happening around.
Dont let those false claims and accusations would be affecting you.