Two questions to start with;
1) Have you bought the correct product? (Teltonika RUT240 devices sold under the product code RUT240 *2**** are certified for use in the Verizon Network)
2) Are you using auto or custom APN? (If using AUTO, try using the custom APN after figuring out what Verizon uses), most often than not the issue turns out to be APN settings.