Transferring unused top.up to new pay monthly bill

[1Leesy1]

My top up runs out on the 3rd, but I topped up yesterday £15. However I have ordered a pay monthly sim which arrives also on the 3rd. Can I transfer the £15 top up to come off my first bill?

[jonsie]

Any credit on the account once the pay monthly becomes active will automatically be transferred and used towards your bills