Broadband Charged Twice from BT and EE since May 2021 for 2 years

[southville2024]

I am a EE customer since 2015. Since 2019, I dropped BT and moved onto EE broadband, so I don't have separate bills from two different companies. 

I renewed my EE broadband contract again on 8 April 2024, and only then I realised I have paid for broadband twice for BT and EE since April 2021 until April 2023. I went through my bank statement and revisited my old BT account to see 2 years' bill paid without usage. 

I never contacted BT on my own to get their broadband contracted in 2021, but it was EE sent an engineer once, where I paid for the fibre broadband installation on the phone. It seems thereafter BT has taken direct debit, because EE was replying on BT with broadband lines.

Can I get a support on this matter? 

I am contacting EE in the first place, because the error occurred when renewing my EE broadband in 2021. This is a long term error and I have not noticed this until I looked into my closed BT account ( which has not been closed!) and see the detail of payment for 'broadband package'. 

[XRaySpeX]

If you migrated from BT FTTC (ordinary Fibre) to EE FTTP (Full Fibre) it was your responsibility to cancel your BT BB contract. EE or OR wouldn't have informed them. They are diff types of line & not covered by Ofcom's Gaining Provider Led (GPL) process.

[southville2024]

I wasn't with EE broadband before. It was only when they switched to Fibre, BT engineer had to come to install. I must have been contacted by BT to pay for the installation on the phone, and direct debit must have been set up then. 

BT replied saying they will refund only two months out of 24 months' bill. This is nearly  £ 660 loss in total.