The Royal Mail is hiring casual staff to help clear the huge backlog of mail in Oxfordshire caused by the postal strike.
Two weeks after the walkout ended, sorting office staff are still struggling.
Royal Mail managers had hoped services would be back to normal by today, but now say it will be at least Saturday before the bottleneck ends.
They blame the delay partly on the large number of letters, cards and parcels sent for St Valentine's Day.
Royal Mail spokesman Floyd Jebson apologised for the continuing delays but said it was not of the company's making.
He said: "There are still bottlenecks in the system. We have employed extra casual staff to try to clear it as quickly as possible. The sheer weight of the backlog, and the additional St Valentine's Day mail, has set us back further, unfortunately.
"We know it is frustrating for businesses and are extremely sad this has happened. We cannot give guarantees. Staff illness could affect things. Anything could happen. But all things being equal, it should be sorted by Saturday."
The Royal Mail has stopped permanent staff working extra shifts because it does not want them to claw back money they lost during the week-long unofficial strike.
Some businesses say they are still suffering. Pet products firm SPH Supplies, based in Murcott, near Bicester, is missing £3,000 in cheques, believed to be stuck in the post.
Owner Sue Hodnett said: "I have not received mail that I know was posted at the end of January. I have called the Royal Mail, but you go through to Reading staff who say there is no backlog.
"The left arm does not know what the right arm is doing. We keep being told there is no problem.
"My business is totally reliant on Oxford postal services. I want the Royal Mail to start admitting the truth about what is going on and how bad things still are."
Freelance journalist Michael Scarlett, of Woodstock Road, Oxford, said he had lost work because of missing post.
He said: "Oxford sorting office staff say they are working on the backlog. But Reading customer service staff said it was still being sent as far as Cornwall.
"You cannot survive as a freelance journalist if mail does not arrive. I am worried as time goes on that everything not already received is lost forever."
After the strike, Oxford post was diverted to other parts of the country to be sorted, but Royal Mail now says it is all being sorted locally.
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