Let me see if I can shed some light on the matter, by discussing how One Bip works.
First, if there is any monetary balance remaining on your one-bip account, that balance will have to be equal to the amount necessary to for Aeria to create a charge for Points.
Generally, when you select One-Bip as a payment source, Aeria charges your One-Bip account, and One-Bip in turns charges your Phone Carrier. So you will see an additional amount included on your monthly phone bill.
As far as I am aware, Prepaid phones are not supported by this because there is no post-charge for Pre-paid services. However, One-Bip does allow you to add a Bank Account associated to your phone number for this issue. (i.e. they will charge your bank account instead of your phone carrier)
There is no way to "Add Money" to your One-Bip account from a funding source such as a "Bank", therefore you cannot "increase" the current remaining funds on your One-Bip account. However, One-Bip does allow for you to receive "funds" to your One-Bip account, much the same way PayPal does with the use of a "Payment Button". This is generally for Merchants to receive funds on their One-Bip account by customers using the One-Bip Button to "send a payment". *That payment* is then charged to their OB Account which is then charged to their Phone Carrier Bill or Bank Account, whichever they have provided.
If there is a "Balance" on your One-Bip account, and you wish to "recover" those funds, you can use the "Withdraw" service, located on the top-right drop down box. This will require you to link your Bank Account to your One-Bip account and process a "Bank-Wire" transaction. (Please note, additional charges may be incurred by using this, depending on your bank.)
How does this apply to you.
When you checkout through the Aeria Billing Page, ad select One-Bip, Aeria will charge the amount to your One-Bip account. You will receive a Text Message for confirmation. Upon Confirmation, your Phone Carrier will be billed by One-Bip. Please note this process could take some time to complete, depending on network latency.
If you are unable to purchase Aeria Points because there is a "balance" on your One-Bip account, and because it is "not enough" to "complete the transaction" (i.e. if One-Bip attempted to say "Non-Sufficient Funds" because they are attempting to use your current funds instead of proceeding to charge your carrier).....Then, Un-register your phone number from your One-Bip account, and create a New OB Account, and register your phone number to that account.
You will basically be "abandoning" the amount you had on that account, in route to a "proper" functioning account, however, you still retain the option of recovering those funds by linking up your bank account, and completing a withdrawal of the amount.
Basically, in short, If there are funds on your One-Bip account, OB will try to process the charge from those funds first. If they are not enough, then the transaction will NSF and will be denied. So you will need to either "Add-Money" to your OneBip Account, or "Withdraw" the balance so that it reads $0.00, so that OB will charge your attached bank account, or your phone carrier.
This is my understanding at least. As I recall the few times I ever used OneBip, I always maintained a ZERO balance on my OneBip account.
Hope that sheds some light on things.
PS. I personally suggest using Off-Gamers as a purchasing source. There you can purchase EPINS usuable at Aeria Games. The more you purchase, the more "OG Store Credit" you build up, and the cheaper your future purchases become (i.e. you may only pay 8$ for 10$ worth of AP) OffGamers is an officially listed source of EPINS for Aeria Games, and they accept many forms of payment in many regions.