Mydin please be environmentally friendly

I do grocery shopping at Mydin weekly. I try to reduce on the usage of plastic bags and bring my own bags to cart the goods. Yesterday when I at the payment counter and asked the cashier to use the bags she refused saying that it is Mydin's policy to used plastic bags. Gosh..! I was furious and tried explaining to her, but she just could not comprehend. So the supervisor came over and made some sill facial gesture and I told her again that I do not want to use plastic bag. And then people started looking at me as though I committed a crime, for not using plastic bags. So I made some fuss and noise and then they allowed me and I came out there determined to send an email to the local tabloid and Mydin. If their policy is not environmental friendly then they better start doing something about it!