A lot of people will find this tricky.
If you want to carry on selling, you may have to be a bit creative.
If you have a printer, you can use Royal Mail only and get your parcels collected.
Is there somebody you could ask to post your parcels once a week?
Would it be worthwhile getting a taxi to the Post Office once a week?
If you used 10 day auctions, you could have 3 posting days a month and perhaps find somebody to take you to the Post Office.
"There are two ways to be fooled. One is to believe what isn't true; the other is to refuse to believe what is true.”
Søren Kierkegaard, Danish philosopher (1813 - 1855)