Price discrepancy

Bounty paper towels in your Zellers store at Northern Avenue in Sault Ste. Marie, Ontario were shown on sale for $9.99 (regular price $13.99). The cashier rang my purchase through at $13.99 plus tax and when I questioned this, she called another employee to verify it.  This employee said that $13.99 was the correct price.  Being "determined", not "stubborn", I went back to the area where the paper towels were and sure enough the sign said "regularly $13.99; save $4.00 and pay $9.99".  I grabbed that sign and took it to the same cashier--I am a senior and the several walks back and forth across that store was bugging me--she looked at the tag I showed her and said "sorry, sale was over prior to today".  I have two things to say, "is it the customer's fault that staff did not remove the sale sign?" and also "now I know why our local Walmart is always busier than the two Zellers we have here in Sault Ste. Marie".  Until today I was a regular shopper at Zellers; however, when I left your store, I went to Walmart immediately and bought the same product for $8.97.  Go figure!  Margaret Simpson