While in theory, you can ask Customer Services to change the feedback,the Response you left is probably the best you will be able to do.
With 98.8% FB and nearly 200 negs and neutrals, the seller is probably used to it.
BTW.
A 98% FB rating is quite poor.
I would probably not consider buying from a North American seller with 98% FB, and for Asian sellers my cutoff is 99%.
In future, read the FB.
Most of this seller's unhappy customers report items that do not work as described.