changing payment methods after auction ends

HI,

I am failry new to selling.

Listed an item as postage signed for only and paypal as only method of payment

four days after winning the item the buyer has made 1 st contact,  asking  that since the total amount of the sale is so low, (  just under $25) would I please consider regular mail as she has difficulty getting to PO to sign

Am I right in thinking that I am only covered by paypal if item is sent signed for? Pretty sure that's right.

 

I am therefore thinking to let her pay reg post costs - 8.25 - if she pays by bank deposit.

But can I do this AFTER auction has ended? I know I can adjust the invoice to reflect the new postage, but can I change the payment method?

Somewhat annoyed she has asked after the sale has ended  - and waited 4 days also- the auction ran for 10 days. - why bid if she didn't like the terms?

However, worried she will leave unfair neg feedback if I don't change post options

Advice re  how to proceed much appreciated

 

Also need to say  I over quoted a little for signed for - but about $2 and had planned to give partial refund - have already done this with recent sales