Go for the refund. There is no reason to believe the replacement would be any improvement.
Once you have the refund, you can contact eBay about the feedback. If it cannot be done, you can add a Response to your neg, explaining that the seller corrected the problem.
Do nothing about the feedback until you have your money back. That's the incentive for the seller to correct the problem.
In future if you have a problem, your first step is to contact the seller.
If that gets nowhere, you can open a Not As Described dispute. The item would have to be returned to the seller with Delivery Confirmation to get a refund through Paypal. The seller may propose other restitution and you can, if you wish, agree. You have 45 days for this.
Then and only then, do you leave feedback that reflects the entire transaction. You have 60 days for this.