The Royal Mail has moved to quash fears that deliveries to homes and businesses in the town could be slashed to two days a week because of a lack of staff.
Accusations were made last week on social media that the town's delivery office had lost 10 workers and there was a threat of cutting back deliveries.
Royal Mail insisted that they would always deliver the mail six days a week.
But it took the Royal Mail press office almost a week to reach anyone in the Helensburgh delivery office to be able to answer the Advertiser's questions.
In an anonymous post on Facebook, a resident said: "Posting anonymously so as not to get him into trouble, but have just been told by my postie that deliveries could be down to two per week.
"Nothing to do with the strike action (which, of course, the RM blames) but a shortage of staff - 10 have left Helensburgh SO [sorting office] and none have been replaced.
"Those remaining have to carry an electronic device which maps their location and speed.
"Just wait, he added, "'til his annual leave - very likely no cover = no deliveries."
And another resident replied: "Post Office not interested in deliverying your letters, no profit.
"They leave it stacked up at the sorting office, take it out. If no time to deliver, they take it back and that's what they call bounced.
"If you're lucky, it will be delivered next day. Last year every postman got extra streets added onto their delivery route to be completed in the same time.
"First class mail is not honoured, don't waste your money on it goes same as the second class stamp."
The Royal Mail said five members of staff in Helensburgh had left, but that there were three new recruits.
In a statement, a Royal Mail spokesperson said: “Improving our quality of service is our top priority and we are committed to restoring service levels to where our customers expect them to be.
“In Helensburgh, mail continues to be delivered six days a week.
"There have been very recent issues with sick absences, however every effort is made to ensure any delays because of this are kept to a minimum.
"Anyone who does not receive their mail on the day they expect will always be prioritised the following day.
"Across our business we have similar plans in place to drive service levels.
"We hope and expect to see further progress in the coming months.”
Royal Mail deliveries in Helensburgh and Lomond, and across the UK, have been badly affected by strike action over the past 12 months.
More than 115,000 postal workers staged 18 days of strikes between September and December last year.
Earlier this month, members of the Communication Workers Union (CWU) voted to accept a deal which will see staff get a 10 per cent pay rise over three years and a one-off lump sum of £500, bringing an end to the threat of strike action.
The deal also includes later starting times for deliveries as well as new seasonal working patterns and regular Sunday working.
But CWU chief Dave Ward said the vote was not an endorsement of the Royal Mail's actions - and added that "many workers simply do not trust Royal Mail group because of the company's lack of integrity and the way they are being treated".
