how do i make a comment under feedback?

[HollyandNoah]

Some little sh*t just left me my first neg feedback.

I was selling some boys stuff and these trainser finished on the 22nd June.
The buyer paid on the 10th July, and opened a not sent dispute on the 13th july and got a refund.
I emailed saying i hadn't even noticed that the money went in because it was my partners paypal and i wasn't expecting the payment so didnt check.
They sent me a blank message back a week later and i replied asking what was meant to be on it. Today i recieve neg feedback saying that my postage was too long. But i didnt post because they were refunded and obv didnt want the trainers anyway. I cant leave them neg. feedback back either!
They only have 14 feedback, i have 199, all + untill now.

I dont know if theres anything i can do, but how do i leave a comment underneath the feeback just to try and explain myself?

[KnickersOnMaHead]

Message withdrawn

[KnickersOnMaHead]

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[HollyandNoah]

tah.. lol that was easy, silly me