The report found that energy providers in general are the companies rated among the lowest in terms of customer service, although SSE rated top among the big six suppliers, with a score of 74 per cent.
Which? executive director Richard Lloyd said: “Long suffering customers deserve better, as once again essential services that we all rely on have been caught falling down on how they treat people.
“Nearly nine in 10 told us poor service puts them off using a company again, so there is a clear incentive to offer service that makes customers smile. Companies at the bottom of our survey should take note: make your customers seethe and you will pay the price.”
Scottish Power said it is “committed” to restoring its service levels to the highest possible standards.
“Last year all our customer accounts were migrated on to a new IT system, which resulted in a very busy period as disappointingly we experienced more problems with the new system than we would have liked,” a spokesperson for the company said.
“The new system is very important as it ensures that Scottish Power customers will be able to take full advantage of all the benefits we anticipate from the roll-out of smart meters in the coming years, and it will allow us to continue adding innovative features to make it easier for customers to manage their accounts. This survey was conducted between May 2014 and April 2015 which was a very difficult period for Scottish Power following implementation of our new system.
“To restore our service we have recruited 500 additional customer advisors to our UK call centres and, since the survey was conducted, our average speed of answer has improved by 72 per cent from 193 seconds in, 2014 to 54 seconds over the last 3 months and we have also seen a 50 per cent reduction in our regulated complaints”.
An Npower spokesperson said that, following “earlier billing system issues”, the company is “working hard” to make improvements to the way it serves customers.
“…the Which? survey is another reminder that there is more we need to do to give our customers what they need – simple, clear and accurate bills and the ability to choose how and when they contact us. For example, through our new, improved mobile phone app,” the spokesperson added.