AFAIK it was a "goodwill" campaign which is now over, so you have a car with a component which has worn out outside of the warranty period and will be expected to foot the bill for repairing it just like with any other component.
Since you have a mail from them stating they would pay for the work you may be able to get it sorted still, depends exactly what the mail says. I'd contact Volvo again ref that email and ask them.
Best of luck.
Cheers,
John