Just because there's something on the package saying $2.90 doesn't make that the total cost. She could've printed out the shipping label at home and then upon getting to the post office, they checked it before accepting it and told her it would be extra, in which case they affix a sticker with the additional amount and the original amount isn't written anywhere. She almost definitely overcharged you if it was $20 for parcel post, but it tends to start at $4.90, not including delivery confirmation (another $.19 if done online) for 1 pound within 1 zone, and two pounds ends up around $8.50 usually. But as some other people pointed out, if it was stated in the auction, it's harder to complain after the fact. Sometimes I'll ask about what seems to be a high shipping cost before an auction ends and I'll get responses ranging from the closest post office is 40 miles away (seems improbable, but I'm sure it exists) to that's simply what they deem their cost of packaging and time sending it out costs/is worth.Yeah, I don't know how on earth this package cost only $2.96 but that's what it said on the postage printout on the package! I couldn't believe it.
It was an unexpected gift from family in Rhode Island and I am shocked they sent it Parcel Post and without any delivery confirmation or anything!
When you finally receive the package, check the postage cost and ask her to refund you the difference! Parcel post should not cost $20!!
In the end I think it's just part of the cost that you have to add in when you're deciding whether or not to bid and it's what you've agreed to once you bid, whatever the reason for the high cost. Of course if they charged you for a particular service and then use another, that's a different story.