Ofcom has urged Shell Energy to “get a grip” on broadband and landline complaints after the firm attracted significantly higher volumes than other providers.
BT Mobile, Virgin Mobile and iD Mobile are the most complained-about mobile operators, according to the regulator’s latest figures.
Ofcom said it is monitoring Shell’s performance closely.
The regulator said: “We have been engaging with the provider and urged it to get a grip on identifying and addressing the root causes of these issues.
“As always, should we identify specific concerns with how our rules are being followed, we will consider whether it is appropriate to take formal action.”
Virgin Media continued to generate the most pay TV complaints, Ofcom said.
Overall, the volume of complaints between July and September were broadly in line with the previous three months.
Sky had the fewest pay TV and broadband complaints, while EE joined Sky as the least complained-about landline providers.
Tesco Mobile, Sky Mobile and EE generated the fewest complaints in the mobile sector.
Broadband complaints were mainly driven by faults and service issues, while landline customers were mainly unhappy with how complaints were handled, Ofcom reported.
Fergal Farragher, Ofcom’s consumer protection director, said: “Overall complaint levels have been consistently low in recent months, but some providers need to raise their game to match the customer service standards offered by their rivals.
“If you’re not happy with the service you’re getting, consider shopping around and moving elsewhere. You could end up with better customer service as well as saving money.”
A Shell Energy Broadband spokesman said: “We always strive to learn from any instances where a customer feels let down.
“Ofcom’s table reflects our position up to six months ago, and since then we have invested heavily and made big strides in our customer service and complaint processes.
“We’re confident that these improvements will be reflected when Ofcom releases its results for the current period.”