Data Plan upgrade delays

On Dec. 13th I clicked "Change Plan" to upgrade from 15 GB to 50GB plan. I did this after I called to confirm that this would NOT require a new "commitment" as we are done our 2 year commitment. I called again on Dec. 16th because the web account showed the new plan in billing but not in Data Usage. I was told that the upgrade was being "escalated" to the next level. I got numerous e-mails confirming the account change. Now it is Dec. 18th and Data usage still shows the 15GB. Please help.