Royal Mail has apologised after householders and businesses in the north complained the service can no longer be relied on.
One business in Dingwall is still waiting for a guaranteed special delivery parcel that has been sitting in the local sorting office for a week.
On Mull, people expecting a Royal Mail delivery on the island are being told when they can pick it up from the nearest sorting office.
And in Islay, residents are still waiting 10 days for post to be delivered.
Investigation into Royal Mail
Today, it was revealed that the company may be sanctioned by Ofcom. The watchdog launched an investigation due to failures in delivering mail within agreed timescales.
That is despite previous assurances by the company that more staff were to be employed on the island.
Alastair Redman, councillor for Kintyre and the islands, said: “Unfortunately the problems with my constituents having to wait up to 10 days for a delivery have returned to Islay and Jura.
“This does not seem to apply to Amazon parcels than seem to be delivered mostly on time, but other parcels and letter are going undelivered.
“Just because the TV film crews from the BBC and STV have gone that does not mean that Royal Mail can slip back into their old habits. ”
He stressed the frontline staff were in no way to blame, but argued Royal Mail need to employ more staff.
He continued: “Royal Mail’s central management has a lot to answer for and my constituents want to see action not more excuses from these executives.
“I will keep pressing them to improve their service.”
Dave Mclaughlin, of Shandwick Supply Co, in Dingwall fears the delay in post could have a devastating impact on his business.
He told The P&J: “We use Royal Mail Special Delivery on a regular basis for urgent parts and tooling, on the basis that is it a reliable service.
“During the last month we have had the odd day when mail did not appear as expected, but this was put down to occasional delays in the system.
“However last week took the situation to a new level.”
10 days without a Royal Mail delivery
He continued: “We have not received mail since Friday May 5 and I have now obtained tracking info on two specific packages.
“One has been with the Dingwall sorting office since Tuesday May 9 and the second, a Special Delivery before 1pm, since Wednesday May 10.”
Mr McLaughlin encouraged others to complain about the service.
A Royal Mail spokesman said resourcing issues was the problem, meaning there were not enough staff.
He said: “We are sorry to hear some residents are experiencing delays.
“This is an important issue, when delays happen every effort is made to ensure post is being delivered, and the reasons behind the delays are addressed.
“The service in the area has been negatively impacted by resourcing issues, including sick absences. Efforts are under way to improve the service, including bringing on agency staff and recruitment.
“We encourage anyone with concerns about the delivery of their mail to please contact customer service on 03457 740 740 or via www.royalmail.com.”