Very high bulb first payment

Hi

I’ve recently just switched to Bulb - we were paying our previous supplier £40 a month but for some reason Bulb have set up a first payment of £62.50 - however I’m unsure why

I’ve tried altering it but until this first payment has gone I’m unable to alter it

Bulb use historical yearly figures divided by 12 for yout monthly dd.
Or using the yearly kWh you submitted.