Sainsbury's UK The plastic bag tax: How Sainsbury's are subverting the reason for having it Internet

Northern Ireland has a 5 pence per plastic bag tax to reduce the unecessary use of plastic bags for enviromental reasons.

Last week I ordered some wine from Sainsbury's online which arrived in recycled boxes buta 40p bag charge had been added to the bill.  I complained (since we didn't receive and didn't want bags) and received a 40p voucher.  This week same thing -another 40p charge for bags even though the wine comes in recycled boxes.

The young lady my husband and I spoke with spoke with on the help line consulted with her manager who said it was 'policy' to charge all customer's 40p automatically whether or not they receive bags and would not be persuaded that this was just wrong. 

With galactic stupidity she then suggested that she send us out the 8 bags we didn't order, didn't want and didn't use and seemed to have real difficulty understanding why this wasn't acceptable (particularly since it defeated the purpose of the bag charge).  Eventually we got her to agree to another refund but it was entirely beyond her to understand why we didn't want to go through this carry on every time we order drinks from Sainsbury's online.

The voucher has not thus far been emailed and we have little confidence that she is capable of raising this as a complaint/ issue on our behalf.  Is there anyone at Sainsbury's who can understand why customers are not happy to be charged for things they didn't order, didn't want and didn't receive?