Not sure if this should be in Accounts and billing REF: Credit Limit and Top Ups

[#1]

Can you add the information to the page https://portal.plus.net/support/phone/credit-limit-and-top-ups-guide.shtml#
If Top up is not used at the end of the month ?
Can any remaining credit be be used up to pay off future bill(s) ?

[#2]

Quote

Chargeable calls made after applying a top up will be deducted from your credit limit - until the top-up is spent

may answer it
However it can't be used for paying for the broadband if this is what you are asking

[#3]

Could it be proposed and revised
That any remaining unused Top Up credit 
Will have the option to be offset towards paying any remaining balance on the main bill
So that
If for any reason the consumer has difficulties, in paying the bill for no fault of their own IE: They dont get paid in time, bank/ building society forecloses, their place of employment go into receivership , their details get stolen and have to close their bank/ building society down etc