15 years with tmobile and getting promised to fix issues but not happening

Hola,

15 years with t-mobile. About 4 months ago added lines under my family plan and all the problem started! Billing all screwed up! Every time happens I have to deal with this! Last 4 months I have been calling and issues arent fix! Please help or at least tell me if you cant fix so I can move on to a different company!