Having trouble renewing my half price discount oyster photocard?

I have a half price oyster discount card that runs out in 3 days times but my weekly bus p needs to be renewed today. I went to the post office to renew my photo card but they say they can't do it otherwise they will get in trouble, I have phoned TFL and they can't help or really don't have any information or I have phoned the benefits office and they can't help. So what it means is that I can't get my half price discounted bus p this week just because my bus p expires a few days before my photo card does