Htc One APN and 4.3

[isacheeks]

I have an HTC One with ATT and I currently have unlimited data. When I first received my phone an ATT customer rep had removed my data for whatever reason and didn't put it back resulting with unlimited data. Since then my APN was not working. I then found one that worked fine which was wap.cingular. Well because of this I couldn't update to Jelly bean 4.3 but I then found a way to update it through my computer rather than over the air. Now that I have 4.3 the APN setting I had used before no longer works. When I enter it, it says "this APN is not allowed on this device". Niether does the APN "phone" work on it as either. Now in order for it to work again ATT has to put back my data on there and I will lose my unlimited. So my question is, is there a way around this so that I don't lose my unlimited without rooting or unlocking my HTC One?