Billing Issue Escalation

I am AT&T Wireless customer for 17+ years. I upgraded my primary wireless line and added a new line early November(BOGO offer). Since then for last 5 months, I have a billing issue and been overcharged $52.78 each month. I went to AT&T store( https://www.att.com/stores/texas/cedar-park/78557) several times as recently as today and also called customer service multiple times. So far there has been no resolution.

Here are the issues with my billing.

1. Been charged $28.10 for number that I ported out to Google Voice on November 12, 2018. This number is no longer an AT&T number but still being charged.
2. I have Mobile Share Plus 9GB Multi line plan for $80. With $20 AutoPay discount and 23% Signature discount, it should be $46.20 and with taxes $50.18. I am being billed for Mobile Share Plus 3GB Multi line $46.20($50.18 with taxes) and Mobile Share Plus 3GB One line $23.10($24.68 with taxes) instead of just Mobile Share Plus 9GB Multi line plan $50.18. So I am being overcharged for $24.68. Also bill needs to reflect the correct plan i.e. Mobile Share Plus 9GB Multi line plan.
3. Also the bill is reflecting incorrect mobile number.

Overall I am being overbilled $28.10+$24.68 = $ 52.78 each month and bill is reflecting incorrect plan and number. I have spent lot of time since November 5 to get this corrected with no luck. So I am writing to you as last ditch effort to get this situation resolved immediately. It is causing me lot of anxiety and tension.

Please look into this and help resolve the matter right away. Thank you in advance for your help and attention to this matter.