Why is that ST Verizon customers aren't getting 4G LTE yet?

Verizon started giving 4G LTE to their Prepaid customers from July 17. Why is that I being a straight talk CDMA-V customer don't have access to 4G LTE? I bought an Iphone 5 Refurbished from Straight talk for $400 which Verizon is now giving for $349. The worst part is that Verizon gives 4G LTE and I am stuck with 3G (Max download speed of 1.24 Mbps
).
