Npower cheque – phone number to claim?

Sar123

Hi all. Does anyone have the direct phone number for N Power’s returns/Refund department?
I closed my account with them back in March and my account was in credit, so they owe me a cheque for £100+. It shows on their records that the cheque was sent, but I never received it, although that’s probably Royal Mail’s fault.
Anyway to cut a long story short, I was given an 0800 number to call but it doesn’t seem to work – does anyone have the correct number, or a number that I can use to avoid going through the whole process of choosing 395349858345 options before speaking to someone?

Thanks.