Royal Mail wrote to striking postal workers today and urged them to call off the unofficial action, which has paralysed services in Belfast.
The company vowed to address genuine concerns among its staff but warned the dispute, now in its 12th day, will cost jobs.
The move came as planned talks between the company and national officials from the Communication Workers Union were scrapped.
According to Royal Mail, an agreement that local CWU officials would not attend the meeting was broken.
The company is expected to make an offer to senior CWU figures in London within the next 24 hours in a bid to break the deadlock.
Michael Kennedy, Royal Mail’s general area manager, today appealed for an end to the rumour and speculation which he claimed had prolonged the strike.
The letters were hand delivered by management in conjunction with a Belfast taxi firm to staff.
Royal Mail confirmed it was happy for a third party to be involved in talks between it and the CWU regarding industrial relations in the Belfast delivery office.
But Mr Kennedy forecast an end to the strike was still some way off.
He said: “After three further days of employees receiving no pay we have this morning received CWU’s response to our proposal.
“This response now places new demands and takes us further away from resolving this dispute.
“This is very disappointing and is only serving to further prolong an already lengthy and damaging strike.”
The manager said the trigger for the dispute, the leak of details of pending conduct cases and a harassment case, should not have been disclosed.
He said it would ultimately be for an appeal or an industrial tribunal to deal with the claims.
Mr Kennedy wrote: “I ask you to consider whether this strike was really a spontaneous event due to ’the climate of fear’ quoted to the media or was it orchestrated?
“Most of you walked out without a full understanding of the background and after two weeks now confusion still reigns about what is really behind this.
“Is it a ’climate of fear’ or are a small minority of individuals who want to influence and reopen conduct cases driving this?”
On the impact of the strike, Mr Kennedy said: “Things look set for a third week.
“Many businesses are already laying off employees as contracts are cancelled.
“Hospital appointments are being cancelled.
“Our customers are already suffering badly.
“Royal Mail is suffering. We will lose jobs as a result.
“As trade unionists, is this what you want to happen?
“Is all this pain what you really want?”
Mr Kennedy also said the action was damaging the company’s bid to fend off competition in a more competitive marketplace.
Deliveries in north, south and west Belfast have been disrupted since workers at the city’s Tomb Street depot began the strike on January 31.