A personal attack is committed when a person substitutes abusive remarks for evidence when attacking another person’s claim or claims. This line of “reasoning” is fallacious because the attack is directed at the person making the claim and not the claim itself.
If you’ve been personally attacked online my advice is to consider failing to engage or delaying engagement. If you must respond, then do so calmly. Take the time to demonstrate there is no merit to statements made and others will think better of you for not losing your cool.
Hopefully you will never need have to deal with a serious attack but if you do and want to see it removed, you need to contact whoever controls that content. Most often, this means that you need to contact the author and/or webmaster of the page and ask them to take down the content in question.