You need to call CS and ask if there is a 20 GB plan available for purchase. The only levels of shared data available online are up to 8 GB/month. The line access fee for each of the 2 new lines would be $20/line assuming you are on the Verizon Plan. If you are on the grandfathered Share Everything Plan and they allow you to increase your data to 20 GB, the line access fee for each of the new lines would be $40/line.
That is wonderful to hear that you're looking to increase your data plan as well as add two lines to your account. I am happy to assist. I have sent you a Private Message so we can go over your account in detail.
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