Record numbers of gamblers complained to the industry regulator last year, new figures show.
The 8,266 grievances lodged with the Gambling Commission in 2018 included 2,135 allegations that betting firms failed in their social responsibilities to customers, as well as 2,227 cases of “non payment”.
Some 109 people said they objected to unsolicited marketing, while 25 complained that an advert “appealed to children”.
The figure was the largest on record since the Gambling Commission’s remit was expanded to include online activity in November 2014 – coinciding with a vast increase in the number of cases reported by customers.
A Gambling Commission spokesman said: “We are absolutely clear with the most senior people in the gambling industry that we expect them to protect their customers.
“Where they fall short of this we will take action.”
Figures released to BBC Panorama under freedom of information laws show there were 273 complaints in 2011, 228 in 2012 and 169 in 2013, before the Gambling Commission began regulating online betting.
In 2015, the first full year of its expanded territory, the regulator dealt with 4,291 complaints.
This rose again to around 8,100 the following year, before dropping to 6,224 the year after.
There were 5,587 complaints made between January 1 2019 and July 8 this year, the figures showed.
Marc Etches, chief executive of GambleAware, said: “Gambling companies have a clear responsibility to make sure their customers are able to gamble in a safe environment, wherever they are.
“With millions of people gambling each year and with gambling activity being highly accessible online, through smartphones and other mobile devices, gambling operators need to actively promote safer gambling messages and campaigns.
“We urge all operators to make people aware of the risks of gambling and clearly signpost to the free help and advice that is available at BeGambleAware.org.”
Gambling companies have come under the spotlight repeatedly in recent years, with then-sports minister Tracey Crouch resigning in 2018 over the Government’s delayed introduction of new limits on stakes for fixed-odds betting terminals (FOBTs).
A £2 cap on FOBTs was brought in four months ago as part of efforts to reduce gambling-related harm.
Last month, five of the UK’s biggest gambling companies committed to a series of measures to address problem gambling, including a major increase in funding for addiction, following Government pressure.
The companies – Bet365, Paddy Power-owner Flutter, Ladbrokes-owner GVC, Sky Betting & Gaming, and William Hill – agreed the proposals to create a safer gambling environment after discussions with the Department for Digital, Culture, Media and Sport.
The gambling firms will significantly increase their financial support for safer gambling, increasing their commitment from 0.1% of their gross gambling yield to 1% by 2023.
This will result in roughly £60 million in funding support from the firms in 2023, and it will remain at that level for the future.
According to a paper by academics in the British Medical Journal, published in May, there are now 33 million active online gambling accounts in Britain, while the prevalence of online gambling has increased from less than 1% in 1999 to 9% in 2016.
The regulator has the power to fine or impose other sanctions on companies who fail to comply with their gambling licences, although it is not able to settle individual complaints.
A commission spokesman said the spike in the number of complaints was related to its expanded remit.
The spokesman added: “We actively want to see consumers being more demanding of gambling companies and we are pushing hard for the industry to improve and put protecting customers at the heart of its business approach. The industry needs to improve and must do so.
“Consumers contact us for many reasons and although we don’t have the powers to resolve individual complaints, we act in ways to help consumers as a collective and have the maximum impact for the greatest amount of people. In some cases we use the information that they share with us to enforce operators to raise standards for all of their customers.
“We are absolutely clear with the most senior people in the gambling industry that we expect them to protect their customers. Where they fall short of this we will take action.”
There are an estimated 23 million people in Britain who gamble, with 10.5 million said to gamble online.
BBC Panorama: Addicted To Gambling will air at 8.30pm on BBC One on Monday, August 12.