Loyalty is a two-way street.
My husband and I used to shop at DeSerres more frequently when we lived closer to this location. We are still on their e-mail list as my husband had a (free) membership. So we ventured to DeSerres for their boxing day promotion of 20% off. The staff would neither honour the coupon we had been e-mailed nor renew my husband's membership, which had apparently lapsed. DeSerres' policy was not to renew on boxing day. We never received any notice that the membership had lapsed, and the staff confirmed that it "just happens after a while".
Since we can buy full-priced art supplies closer to home any time, we left.
The only reason this store gets two stars instead of one is a reasonably helpful sales associate. Of course, I had to find her first... chatting with another sales associate in the back of the store... but once I managed to break their conversation, she was helpful and knowledgeable.