[Energy provider you're switching to]
To [details of the energy switching department]
Account Number: [details]
Date of request to switch: [date]
On [date] I requested that my [gas/ electricity] [gas and electricity] supplier [name] switch my [gas/ electricity] [gas and electricity] supply to you.
The switch was completed by [set out details of how you switched eg by phone, online or name any switching service that you used].
I was advised that the switching process would take [number of] weeks but [number of] weeks have now passed and I have still not received confirmation that the switch has been completed.
I would now request that you confirm by return of post the date on which the above switch was completed or alternatively the date on which the switch will be completed along with an explanation for the delay.
I look forward to hearing from you.