Utility supplier Spark Energy faces an investigation by the industry regulator Ofgem after complaints from customers.
The energy watchdog said it had launched the probe into the Selkirk-based supplier after receiving information about poor customer service at the supplier.
The five-old firm, which has around 65,000 customers was recently featured in a TV consumer programme after some customers claimed it was “impossible” to switch once they were tied into an agreement with the company.
“Suppliers are required to receive, handle and process consumer complaints in an efficient and timely manner,” Ofgem said in a statement.
“Suppliers are also unable to block a customer from switching unless there are valid outstanding charges.
“Ofgem’s rules include provisions that if a customer provides a meter reading, the supplier must take all reasonable steps to reflect this reading in the next bill.
“These billing rules also state that the supplier must take all reasonable steps to ensure that fixed direct debit amounts are based on the best and most current information available.”
The BBC’s Watchdog programme said it had received around 200 complaints from customers of Spark in the past year.
Customers had also reportedly experienced missing bills, struggled to get refunds when in credit and found meter readings not being recorded properly, while suffering difficulties in getting hold of Spark’s customer service team.
Spark Energy was not immediately available for comment.