"Functions" is correct; "functionality" is a more abstract idea and would not be appropriate in that context.

Is functionality the same as function?

The subtle difference between the two words is this: functionality refers to the capability and suitability of a thing, whereas function refers, without value judgment, to the action a thing performs or is intended to perform.

Is functionality a proper word?

Functionality is an adjective which means of or relating to a function or functions . They might have used this word as they have already mentioned one function (i.e. fast forward ). Although, there is no obligation by your cable provider to use correct grammar.