A Question About Postage Due

Here's a question not really about collecting.
I sent a letter in the mail to a address in Canada and the letter was returned as there was 23 cents insufficient postage. They placed a sticker on the envelope stating I need a extra 23 cents and please remove this sticker and add the appropriate postage, Only thing is all the other stamps I used have a big old yellow line striked through them is it still ok to just stick 23 cents of stamps and drop in the mail box or are the stamps with the yellow lines now regarded as cancelled. I am sure some body has come across this problem before.
It was for stamps that one of the members here won on auction, Thanks

Had that happen several times with small packages-- I tend to guesstimate the weight and usually lean to the lighter side which usually works in my favor. When I called Canada Post they said just add difference and send - Told them I wasn't comfortable sending this way and wanted replacement stamps so they mailed me some new ones free. When you peel that notice back it leaves a clear film so they should realize if it gets rejected automatically.

I had an envelope with stamps sent to me that I won on ebay. USPS decided that the envelope was too thick to be classified as a letter, so it became a package. My mail man left a pink slip in my mailbox saying that I had a package at the local PO awaiting postage due. I had to go to the PO and pay the $1.07 due to get the package.

Thanks
The letter was covered in 5 cents stamps a nice cover now covered with yellow marker.
I do feel that Canada Post ruin what could have been a nice cover. I think I will call them up Nitrolures and see if they will send me out some stamps. Don t you think that the sticker would have been enough and not a marker, or maybe a hand cancell but that be like asking to win the lotto

I recently had a notice of a package awaiting me postage due. It was a book from an auction house I had been waiting on. They had sent it Media Mail to my previous address I had registered with them, it was forwarded to my new local PO, which held it until I paid the full Media Mail rate again, the explanation being that 3rd class rates don't forward. I was glad to pay it, but the package was mailed with a label and only had ballpoint markings-- and it had been pretty well mauled by the time it got to me. Ugly. Thankfully the book was OK.

I gotta add that if that cover was as nice as the one you sent me I wouldn't be happy with Can post either. Go both barrels loaded and tell them it was a classic philatelic creation and they ruined it. As soon as I get a chance I'll scan and post the awesome cover you sent me.

Had an envelope returned to me once but no yellow marker. I added stamps and re-mailed but now wish I had saved the whole shebang as future collectors will want that postage due cover With label as a collectible item.

Any extra markings or labels are very collectible but when it happens to you it is frustrating and you just want to clear the mess up and get on with it.

I think just adding stamps will be OK. They can tell from the clear sticker over the address that it was returned for postage due and so will just look to see if the total postage, before and after the yellow marker, is sufficient.