Trying to get a refund once left

I switched energy suppliers on 18th October and am in credit with my account.
My new supplier has had my final readings which were sent to the independent body who have sent them to Bulb so that my account can be closed and my credit refunded.
My new supplier says that Bulb should have paid me by 29th November but they haven’t.

Despite numerous emails and phone calls to Bulb they haven’t paid me saying they need my electricity reading to close the account.

My new supplier says that Bulb will have received this information in November.

Has anyone else had problems getting refunds when they left ?

Thanks.

Hi - yes I switched in November and still awaiting a credit.