Pay as you go credit

Hello
I paid £ 25 into my pay as you go credit account , I originally thought this would be used to pay my monthly pay as you go subscription but this is debited from my debit card each month so the £25 is not being used
can the £25 in my pay as you go account be used to pay my monthly subscription ?

It can be done Fonzie however you do get double the data if you purchase the plan without using your credit. More information here. Please let me know if you have any questions.