I live in a remote area with crap broadband (as do most of the parents of kids at my sons' school) and have spent a good half hour, frequently, trying to pay on the appalling Parentpay site. It was faster to shove a tenner in an envelope. Way faster.
My kids' school insists you pay a minimum of £10 per child not per family - so with two kids there, at the start of some weeks I'd have to find at least £20 which I don't always have.
Since the crap Parentpay came in, my older son has agreed to have pack-ups and the younger prefers school dinners but rarely gets them.
There was at least one occasion recently where I paid at 8:30 AM (and could prove it via the receipt) and at mid-day my son was told the money still hadn't gone on so he couldn't eat.
Since Parentpay came in, my sons tell me that one brother is not allowed to buy something then pass it to the other, either.
I hate the fact private companies and individuals can make money out of the fact schools want this service. It should be taken from them, and given to local councils to operate, so someone isn't making money off the back of the fact our kids want school lunches, and schools don't want the hassle of administering that any more.