I've been selling for around 6 years now and received my first negative feedback. I'd understand it more if it was something I actually did incorrectly but as far as I can tell this just comes from impatience.

The Negative Feedback - 'the delivery took forever... usually when i order from USA it comes to Canada in 3-5 days, for this order I waited 20 days... my orders from China came faster than that. For a bit i felt like i was being sc*m'

This was an international shipment to Canada from the US using the international shipping program. The order took 13 business days which is not the 20 days as they wrote even if weekends were included. I never received any message from the buyer regarding a sc*m concern.

Other issue that popped up shortly after receiving the negative feedback was the sold order page is now marked with 'This order has a listing with a policy violation.'. As in I had the page up with no warning, refreshed and the warning was there. Really confused about this. The item was a purse.

I've already requested feedback revision, asking kindly but still laying out the facts about shipping and estimates regarding the international shipping program. I don't have much hope they'll be willing to change it but it can't hurt.
I'm wondering if there is anything else to do given the nature of the negative feedback feeling really unfair or if it's just a block and move on kind of thing. Input is appreciated!

*Censored due to auto flagging of rule 1 not letting me post, not a real sc*m just accusations :,)