Data plan change removes data?

I was previously informed that a change in data plan would just mean that the new plan adds on to the existing amount of data already available. I had around 12gb of data stored on an 8gb per month plan. I wasn't using all of it each cycle so it added up into the [phone number removed per the Verizon Terms of Service]gb range of data left. After being told changing data plans wont affect anything I decided to switch to the 3gb per month plan on the paying cycle. After the payment it shows me to have 100% data with 3gb/3gb where as it previously showed me I had 100% data with 12gb/8gb. Just wondering if that changed or was ever a thing to begin with.

Re: Data plan change removes data?
Master - Level 1

They weren't going let you have 15 GB if that is what you were thinking. You're new plan allows for 3 GB that is what you got. Also rollover only carries over for 1 month adn if you don't use you lose it. Not to mention I don't think it exists for new plans anyway. You obviously didn't use it since you said as much. Also the 3 GB plan has a double data promo so you should be showing 6 GB not 3 GB. I'd check into that.