The first needs context to make it grammatical.
For example 'I used to be beaten whenever we played, but now I win occasionally'
or 'I used to be beaten for slurping my soup - that's how brutal they were'
Without some such context (which, incidentally, makes it clear what sort of 'beaten' you mean) the sentence is very odd.
'It used to be being done' works if the speaker is referring to a process. Example: 'A check of everyone's passport used to be being done, but now the Border Agency just doesn't have the manpower.' Again, without an explanatory context, it sounds very odd.
They are both barely grammatical, but can be justified in a very specific context.