O2 price unfair increase

Hi, as VM volt customer, I had a letter about the O2 £2.50 price increase, a couple of points I would like answered.

Do you lose the Volt benefits? I say benefits, but I think there is only one that affects me, M350 boosted M500. I don't know if that will make real difference when streaming something? I can get a cheaper Sim only from what I am paying now, so is the slightly faster speed worthwhile anyway?

Why do you only you 30 days from date on the letter to cancel, shouldn't be from increase date?.

Also in the six or so months I had the O2 deal (been a VM customer for many years), I haven't able to log on to my O2. I have contacted O2 a few times on this they say they are working on the problem!

Please help