My OH got an upgrade with Orange a few years ago (Mar 2008 to be exact)
Orange had been taking DD for both old and new contracts since March 2008 until June 2013)
My OH got a 'gesture of goodwill' refund from Orange for the last 6 months overpayments (~£200)
At the time I thought this was a refund of all overpayments, however now it's come to light this was only the tip of the iceberg! From trawling through statements the actual overpayment was just over £2k.
Yes, I know she should have checked statements regularly, but excusing that, it does not give Orange the rig