(Providence, RI)--Stop and Shop customers are getting a letter of apology as a worker strike affecting Southern New England stores stretches into a seventh day.Stop and Shop is committed to resolving labor negotiations as quickly as possible so employees can return to their jobs and so the stores can get back to better-serving the community, according to the message sent Tuesday by company president Mark McGowan.A full-page ad taken out by Stop and Shop in newspapers yesterday says "we're trying to be fair".A joint response by the five locals of the union representing the workers criticized the ad and the company's latest proposal, claiming among other things that it would drastically increase out-of-pocket health care costs.