Unfortunately they can. Have you heard of the motto "We have the right to refuse service to anyone for any reason." While this may be a stretch of a reason due to your past employment, they are legally allowed to deny you the right to shop there.
However, there are a few exceptions and without writing an entire legal column, I'll explain the one that is most prominent. If that store is the only store in the area that houses a particular product needed for your safety or survival.
e.g. If you worked at a pharmacy and they were the only pharmacy in the city or town, then they could not legally refuse to allow you to shop. However, a gas station, grocery store, or other commodities store where their are more than one, can.
a fatty
Employers are NOT restricted in making factual comments on former employers. They are liable only if they make knowingly false statements. Prospective employers can ask about your former job, too.
The only questions that are truly legal are if the employee worked their and what their position was. They can also ask if they are eligible for rehire.
They can ask anything they wish, though there are some limits regarding status that could lead to discrimination. And answers by the former employer may be limited by various privacy statutes, but anything that is a matter of public record can be shared. Most former employers will only confirm the dates of employment and the position(s) held.
Submit, in writing, your version of the events which caused you to leave the old company to your new employer (but only if they ask for it).
Those that are job related. For example an employer may not comment about an employee's or former employee's sexual orientation.
Absolutely not. That would be a financing question.
>a co-worker at that job who has since left the company
What is the store's most sold item.
"What if previous employer will not return a call for a reference?"
It means your relationship to the referee. i.e current employer, previous employer, mentor, personal tutor, head teacher and alike.
A prospective employer can ask ANYTHING. It must not consider race, sex, religion, age, or disability if it has more than 14 employees.