BT has insisted it is investing heavily in improving broadband services in rural parts of the UK.
The Observer spoke to several BT broadband customers living in the countryside who were unhappy about getting speeds much slower than those they had been promised.
For instance, Karen Oxley of Craster in Northumberland said she was struggling with speeds of 7Mbps, despite purchasing an Infinity 1 package offering a minimum download speed of 45Mbps.
She said BT had "advertised and sold something it cannot deliver", as a BT engineer established that since superfast broadband was not yet available in her area, her line could never deliver more than 7Mbps.
However, BT has stressed that it checks what type of broadband is available and gives each customer a personalised speed range estimate before they place their order.
"If a customer consistently gets lower speeds than we estimated, we try to improve it," the provider said.
"Where we can’t do that, the customer can cancel the service without charges."
BT also said it is spending more than £3 billion on rolling out fibre broadband, which is now available to more than 26 million homes and businesses across the UK.
The company added that Ms Oxley's slow service is down to the length of the fibre cable from the street cabinet to her home.
This comes after the Advertising Standards Authority confirmed new rules on advertising broadband speeds are likely to be introduced in 2017.
The watchdog stated that allowing broadband providers to promote speeds that are achievable by just ten per cent of customers is potentially misleading and means the majority do not get the speeds they expected.