How do I sort this?

[doubtanddither]

I haven't got much expecting of EBay. Won and paid in full via PayPal on Wednesday 25th, got a message from seller saying it had been sent first class on Friday 29th.
I haven't received the item so sent a message asking if they'd got proof of postage. She replied that she'd see if she could find it but I've had no response since Friday 1st.
What's the protocol, wait two weeks or raise it with eBay.
The value is £36.

Wednesday 25th, got a message from seller saying it had been sent first class on Friday 29th.

Do you mean November? There was no Friday 29th... Friday was the 27th.

I would wait a little longer to see if it turns up, it's only been just over a week since it was posted, if you meant the 27th. Royal mail is overwhelmed with parcels at the minute, and things are taking much longer to arrive.

If they've stopped responding just go ahead and contact eBay. Agree with above posted about the parcel delay, but when they stop responding there is usually a reason.

I would wait a while, royal mail are under insane stress - I have a small business and even signed for services are taking between 1-2 weeks in some places!
that being said, if it hasnt arrived after 2 weeks raise it with ebay, if she does not have proof of postage or a tracking number they will rule in your favour