The Money Advice Trust (MAT) dealt with 17,766 calls to its National Debtline from people about telephone debt last year, compared with 5,830 in 2007, the year the iPhone was launched.
According to MSN, the trust also records 13,389 calls between January and August, a 15% increase on the same period a year ago.
It said that in 2007, one in 25 calls (4%) were about phone debt, but has increased to one in nine (11%).
The charity suggested that the rising use of smartphones is a factor behind the increased number of calls.
Many people see smartphones as a must-have product and according to Ofcom figures around two-fifths (39%) of UK adults own one.
Joanna Elson, chief executive of the MAT, said:
“Smartphones have in many ways revolutionised our lives, but we've certainly been made to pay for the privilege.”
“A family of four with two parents and two teenagers could quite easily be paying around £140 a month for all four to have a smartphone – more than the average UK energy bill.”
“For 42% of smartphone owners, the phone is their sole internet access point, so they are quite reliant on keeping it running.”
Ms Elson said that when people take out a contract for a smartphone, they are “in effect taking out a loan to pay for the handset”.
She also expressed her concern:
“When people fall foul of that monthly fee, they can find themselves with a growing debt problem. The figures suggest this is happening more often in line with more people taking out expensive smartphone contracts.”
Ms Elson said there should be responsibility “on both sides” and people should only take on contracts after carefully considering whether they can afford them, while mobile phone companies should treat consumers in financial difficulty with understanding.
She said people can seek free advice on budgeting and prioritising their debts through the charity's online tool www.mymoneysteps.org.