Hi @Wendy ,
Welcome to the community!
In case you added $10.00 to your account and it happens that there is still a remaining Mobile Data to the account the $10.00 will not be automatically converted to 1GB you may need to manually add prepaid mobile data to 'My Account' online. If this is the case, the $10.00 will be consumable for Call, SMS or MMS.
We did an article that you may find helpful. This will guide you on how to manually add mobile prepaid balance. Feel free to visit the link below.
Let us know how it will go.