Please accept my sincere apologies for any inconvenience that you might have experienced.
In order to get the clarification about the same, i would suggest you to contact AT&T dedicated orders department at 1-800-288-2020 (Monday to Friday between 8am to 7pm CT Saturday between 8am to 5pm CT Sunday: Closed). They will check your accounts details, availability of speed plans in your area etc. and will let you know the exact time frame associated with the upgrade.
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*I am an AT&T employee and the postings on this site are my own and don't necessarily represent AT&T's position, strategies or opinions.