Richard Harrington MP criticises Watford Royal Mail
Watford MP Richard Harrington has labelled changes to the town's postal service as "absolutely appalling".
The Conservative MP said he would press Royal Mail to give compensation to constituents who had not received their post on time.
The Communication Workers Union said the problem had been caused by postmen being given larger rounds to complete.
Gary Burgess, Royal Mail's Thames Valley delivery manager, said it was trying to balance "cost and service".
Mr Harrington said people had been "totally disrupted" by the changes in recent weeks.
He added: "I think it's absolutely appalling and I intend to really press [Royal Mail] for compensation for those people who have lost money."
Norah Hackman, who lives in Ashfields, Watford, said: "It's been going on for about six weeks now.
"Sometimes I have had no mail for two or three days which is unusual, and a couple of times it has turned up as late as 17:00 and 18:00 BST."
Abdul Khalifah, of the Communication Workers Union, said some rounds from the Ascot Road depot, in Watford Business Park, had increased by 200 to 300 drop points.
He said: "They [postmen] have been given X amount of drop points to do within a certain time frame which is totally unacceptable and unachievable.
"The new methods that have come in have put undue pressure on the postmen. The normal time of leaving the office would be about 10:00 BST to get their deliveries finished by 14:00 BST.
"We've [now] got postmen not leaving here until 11:00 BST or sometimes 13:00 BST so it's been impossible for them to do a complete delivery of their mail.
"It's all about saving money," he added.
Mr Burgess said the volume of mail being dealt with from the Watford delivery office had dropped by 20% over the past five years and it was handling about 100,000 fewer letters per week than two years ago.
He said: "My deliveries in Watford cost me twice as much to make as they do in other parts of the region which I manage."
He said managers were now checking that routes had been planned correctly and staff were working at the appropriate rate.
He added: "My anticipation is that we will have the routes back on an even keel by this time next week."