Probably worth doing but from my experience, it won't do a lot of good.

I once bought some cartons of spread which were only part filled. Obviously a manufacturing fault but the duty manager was rather rude when I suggested that perhaps they should check the remaining stock, implying that perhaps I would like do do his job for him.
Contacted the manufacture who was most concerned and sent me compensation and their assurance that they would take it up with Sainsburys themselves.

On another occasion in Savacentre they refused my Credit card for an electrical purchase saying that it had been declined when they phoned for authorisation. They also declined a couple of other cards for the same reason. Very Embarrassing in front of a number of other customers.When I went into Barclays they checked and told me that they hadn't received any authorisation requests on my cards that day, so I can only assume that the phone calls were never made. I spoke to the duty manager who said the assistant concerned had now 'gone home', and I never did get any further response.

Tescos Customer Service on the other hand I can't fault. On a recent occasion there was a slight problem with my Online shopping and when I phoned they accepted my complaint without question gave me a full refund and a £5.00 voucher in compensation.