buyer left negative feed back after agreed to cancel and refundebay wont help

[red_magpie]

There is nothing in the feedback to qualify it for removal.

EBay won't get involved in private agreements beteen the seller and buyer.

All refunds, whatever the reason, should be processed through eBay's resolution centre. If this had been done, this dispute would probably never have arisen. Or if the buyer falsely claimed you hadn't complied with the procedure, and eBay's records showed that you had, the feedback may have been removed.

[plpmr]

"agreed" in what way?

The feedback says you refused to honour the transaction.