I’m not the original poster so don’t have a stake here, but in general unless I was really upset no, I would simply use the ratings/comments built into the storefront. It’s generally more effective since it’s seen right before purchase.
As far as the link, vendors can obviously always directly refund but there then comes into play the problem of Epic’s 30% if you aren’t doing it through them. The process I was referring to with Unity is actually through them but requiring the publishers approval so that you don’t actually lose money doing the refund. Also, it’s generally better to do it officially anyways since you can check the invoice number first.