Former managers, supervisors and baristas were banned from entering any Costa Coffee store and told police would be called if they did, a letter to former staff members said.
Student Nick Bulic, 19, who lives in West Street, Selsey handed in his notice in early August but received notice of the ban five months later.
He said that, after a manager left, staff members handed in their notices in June and served their two week notice period.
“I hadn’t been in until October 8 and I went in and spoke to the new assistant manager who said I was banned. I asked her to check, then I was told I wasn’t banned and since then I haven’t been in.”
Nine former members of staff were given the ban from all Costa stores, Mr Bulic said.
He added: “It was fully unexpected. I hadn’t been in there for months. I left five months ago so I don’t see the point in them doing this — I like Costa and I like coffee, no-one breached the contract, I left on good terms. It was weird.”
The letter, which has been seen by the Observer, reads: “Following your recent behaviour at the Selsey store, I am writing to inform you that Premiere Coffee Limited and Jurassic Coast Coffee Limited [trading as] Costa Coffee have placed you on a company banned list.
“This means that you are permanently banned entering all Premiere Coffee and Jurassic Coast Coffee stores. You are not permitted to enter a store for any purpose; this includes using the customer toilets or using the building as a walkway between places.
“In the event that you ignore this ban and enter a store, the police will be contacted immediately.”
Emma Cooter, 22, who lives in the High Street, was assistant manager at the store and also received the letter..
She said: “It’s a horrible situation. We would put so many hours into the shop. I think its disgusting. There was nothing to it. I left four months ago and I hadn’t been in speaking to anyone either. I don’t understand why they would have to have the police escort me out. What a waste of police time.”
Costa Coffee has been approached for comment.