The Amplified Bible is one person's interpretation or paraphrase, interweaved throughout the text, supplying arbitrary meanings where they choose. Here is 2 Peter 2:17-22 in the NET Bible, a literal translation:

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2:17 These men are waterless springs and mists driven by a storm, for whom the utter depths of darkness have been reserved.
2:18 For by speaking high-sounding but empty words they are able to entice, with fleshly desires and with debauchery, people who have just escaped from those who reside in error.
2:19 Although these false teachers promise such people freedom, they themselves are enslaved to immorality. For whatever a person succumbs to, to that he is enslaved.
2:20 For if after they have escaped the filthy things of the world through the rich knowledge of our Lord and Savior Jesus Christ, they again get entangled in them and succumb to them, their last state has become worse for them than their first.
2:21 For it would have been better for them never to have known the way of righteousness than, having known it, to turn back from the holy commandment that had been delivered to them.
2:22 They are illustrations of this true proverb: “A dog returns to its own vomit,” and “A sow, after washing herself, wallows in the mire.”
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Given the preceding context along with this, it seems clear that these false teachers were never regenerated. They heard the gospel but did not accept it. Instead, they used it to trick people into leaving the true teachings for lies that would enslave them. The fact that they are described as pigs and dogs that had merely been washed on the surface but inwardly had never changed indicates that they did not get and then lose salvation. They never had it. Plus, we cannot simply ignore all the other scriptures which show the irreversible promises of God the moment we believe (see my first blog entry).

You can see the difference it makes to read the passage itself in context without someone's interpretation included. Hope that helps.