３．電話をかけても、アナウンス等に従って操作したりせず、すぐに切ること。

．、、。

3. Even if you make a call, do not follow the instructions from the announcement or operate anything — hang up immediately.

Literal

3. Phone-call [obj-を] place-[even-ても], announcement [etc-に] follow operate-[one-thing-たり] don't-do-[without-ずに], immediately hang-up thing.

A numbered instructional bullet point, probably a warning about phone scams. Ordinal 3. followed by a period is standard numbered-list format. 従って is the て-form of 従う ('to follow, to obey'). ~たりせず stacks the non-exhaustive listing particle たり with the formal ずに for 'without doing things like X.' 切ること ('hanging up') closes on the nominal こと, a common pattern in formal instructions where a verbal noun functions as an imperative ('one must do X').