NHS data shows more than 77,000 calls were abandoned before being answered, up from 27,652 – 17.4 per cent – in June.
It comes amid concerns that delays to the 111 service are piling even more pressure onto ambulance services, as those unable to get through dial 999 instead.
Figures also show that NHS staff answered the highest number of 999 calls for any November on record, an average of around one every three seconds.
Demand for NHS 111 services also remained high, with almost 1.4 million calls answered last month.
Calls are being made by the Liberal Democrats for a recruitment drive of NHS 111 call handlers to help bring waiting times down.
The political party says it has carried out research which revealed that it took an average of 24 minutes for callers in the West Midlands to get through to the NHS 111 service in September – more than double the average wait of nine minutes faced by callers across England during the same period.
NHS figures show that 77,857 out of 165,424 calls made to the NHS 111 service in September were also abandoned before being answered.
West Midlands Ambulance Service, which took over the service in 2019, says calls can take longer to answer due to high demands facing the NHS and has apologised for any delays.
Bosses at the service say hundreds of new call assessors are already being recruited and will be trained to take both 111 and 999 calls.
A West Midlands Ambulance Service spokesman said: “The whole of the NHS continues to experience high levels of demand, including the 111 service.
"This means that at times it can take us longer to answer calls, for which we apologise.
“The additional funding announced by NHS England in the summer means that we are recruiting hundreds of new call assessors, who are being dual-trained to be able to take both 111 and 999 calls.
"The trust is also recruiting more clinicians such as GPs, nurse practitioners and mental health nurses.
“We’d encourage those who require urgent medical advice to utilise the 111 online service in the first instance at 111.nhs.uk
"Here you can access self-care advice, be given an arrival time if you need to go to A&E, request a clinician call back and get a face-to-face appointment if you need one.”
Like 999, 111 is free and available 24 hours a day.
It is a non-emergency service which offers urgent health care assessment and can signpost people to the most appropriate care for their condition.
This could be self-care, a GP, local pharmacy, walk-in centre, the emergency department and the service can arrange for an emergency ambulance if required.
West Midlands Ambulance Service covers the 111 provision for the whole of the region except for Staffordshire.
When patients call 111, the first voice they hear is of a specially trained call assessor who will take them through a series of questions to determine how to help.
There are also a team of clinicians on hand within the control room who are able to provide additional assessment and advice, when required, over the phone.
They include GPs, nurses, pharmacists, paramedics as well as dental and mental health nurses.
Helen Morgan, the Liberal Democrat candidate standing in the North Shropshire by-election, said: "People across our area are being left on the end of the phone due to the under-resourcing of the NHS 111 service.
"It shows that our local health services are being neglected by the Conservatives who are taking them here for granted.
“These huge delays to the 111 helplines pose huge knock-on effect to other services that we already know are under immense pressure.
"Behind every one of these calls is someone looking for medical advice, sometimes after struggling to get an appointment with their GP.
“If the Government don’t take action, they risk piling even more pressure on our ambulance services that are already on the brink."