The Royal Mail have spoken about working to get a more consistent delivery service back in place after weeks of disruption.
The service has said it is working to get the full service back up and running in response to complaints from residents in Wolverhampton about a lack of deliveries over the last six weeks.
A resident in Wolverhampton, speaking to the Express & Star, said they had not received any letters for six weeks and had been left having to queue for nearly an hour at the Sun Street post depot to pick up their post.
They also said that they and other residents had missed important appointment letters and had raised concerns with Wolverhampton West MP Warinder Juss.
In response, the Royal Mail said it was working hard to get the majority of mail delivered, but had been hit by short-term pressures, including having to clear parcels first to keep offices safe and post moving through the network.
A spokesman for Royal Mail said: "We know how important timely letters are and want to reassure customers that the overwhelming majority of mail continues to be delivered on time.
"However, there have been short-term pressures affecting certain routes.
"The festive period is our busiest time of year, with volumes more than doubling, followed by poor weather earlier this month which affected some deliveries.
"We’re working to restore a more consistent service as quickly as possible.”
The mail provider also looked to answer an accusation that it was prioritising parcel delivery and that postal workers were being told not to deliver letters, explaining how parcel delivery had come first due to the busy festive period and increase in parcels.
The spokesman said: "Our aim is always to deliver letters and parcels on time.
"However, during Christmas and other exceptionally busy periods, delivery offices can become very busy. These are typically older buildings built for a time where letters were the primary item.
"Now, with the increase in parcels, and them taking up far more space than letters, their large numbers can block walkways and create health and safety risks.
"In those moments, clearing parcels first is sometimes necessary to keep offices safe and to ensure all mail, including letters, continues to move through the network.
"Ofcom has looked into this claim previously and found no evidence that Royal Mail instructs the prioritisation of parcels over letters outside of these recognised contingency plans."