Premium Text messages are messages received from a third party service that charges your account no matter if you have unlimited texting or a bundle.
You can have this service blocked if you call Verizon.
Hope this helped.
Premium Text Messaging refers to special programs that require an additional fee to subscribe. A premium charge for the subscription is billed to your mobile phone account or deducted from your pre-paid credit, in addition to the standard messaging rates that will be billed for all messages that originate from or terminate to your handset. Premium Text subscriptions are initiated through special numbers, which are 4, 5, or 6 digit numbers called ‘Short Codes’, and always require your consent for the purchase before any messaging content is distributed or participation in any premium messaging program is allowed. Examples of Premium Text subscription campaigns are: