The Kenilworth Avenue resident says she and her husband have not received any post for around eight days and are unable to get the town’s sorting office.
As a result her partner, who is housebound, did not attend a recent hospital appointment.
A Royal Mail spokeswoman said staff at the Knutsford Delivery Office are determined to minimise any postal delays due to ‘resourcing challenges’.
The resident said: “I’m just appalled. For what the Royal Mail are charging, I think it’s shocking.
“My husband is under three different hospitals at the moment. We’re sent regular letters and we’re just not getting anything through.
“We’re waiting for urgent medical letters and nothing is coming through.
“It’s difficult getting appointments these days, so to miss one due to not receiving a letter about it is even more frustrating.”
The Royal Mail spokeswoman said: “Posties at the Knutsford Delivery Office are working hard to ensure any delays due to resourcing challenges are kept to a minimum.
“Every effort is taken to ensure post is being delivered to all addresses at least every other day.”
The Kenilworth Avenue resident was also concerned for her neighbours, many of whom are in their 80s and 90s themselves.
She added: “They’re very vulnerable and don’t use emails. They’re relying on letters and things in the post as well.
“These letters are vitally important for people.”