Summary: Sometimes it may look like a duck, walk like a duck and quack like a duck, but it is not a duck. Therefore we need to duck false prophets and their message.
Isaiah 8:19 And when they shall say unto you, Seek unto them that have familiar spirits, and unto wizards that peep, and that mutter: should not a people seek unto their God? for the living to the dead?
20 To the law and to the testimony: if they speak not according to this word, it is because there is no light in them.
Be careful that the prophets/prophetesses you listen to are not really soothsayers/fortunetellers. One famous person claimed to have received the gift of prophecy after an encounter where she looked in the eyes of a huge snake. That gift was not from the Holy Spirit. Others have been found to be plagiarists, not prophets and yet people still hold to their teaching.
If what they say does not match Scripture or the "law and the testimony" they are false prophets. The Holy Spirit will never change or be in any way contrary to what He was intimately involved with writing.
2 Corinthians 11:13 For such are false apostles, deceitful workers, transforming themselves into the apostles of Christ.
14 And no marvel; for Satan himself is transformed into an angel of light.
15 Therefore it is no great thing if his ministers also be transformed as the ministers of righteousness; whose end shall be according to their works.
Just because they say they are Christians does not mean that they are since the enemy often wears a disguise as the deceiver that he is.
Deuteronomy 18:20 But the prophet, which shall presume to speak a word in my name, which I have not commanded him to speak, or that shall speak in the name of other gods, even that prophet shall die.
21 And if thou say in thine heart, How shall we know the word which the LORD hath not spoken?
22 When a prophet speaketh in the name of the LORD, if the thing follow not, nor come to pass, that is the thing which the LORD hath not spoken, but the prophet hath spoken it presumptuously: thou shalt not be afraid of him.
A prophet has to be 100% accurate. God speaks very clearly and accurately all the time. A soothsayer/fortuneteller may be accurate once in awhile and even more so if aided by the dark side. God's prophet is never wrong.
Indeed, even if God sends a dream to Pharaoh he does not understand or writes Mene Mene Tekel Upharsin on a wall He sends a Joseph or Daniel to make things clear. They do not murmur, peep or are vague.
If God required 100% accuracy for His people in the OT so they could discern a false prophet how much more so do we need that standard for discernment now when we are told false prophets would abound and that the Anti-Christ would come with lying wonders so good that if it were possible it would deceive very elect.
A false prophet who even had his prophecy come to pass, but tried to lead the people to another God was in even deeper troubled than being ignored. False prophets have introduced many other "Jesus" personages creating cults. No matter what they do that looks like prophecy or spiritual giftings it is only what is spoken of in Matthew 7:21-23.
1 Thessalonians 5:20 Despise not prophesyings.
Indeed, but be discerning and despise false prophecies and mark those that cause division by their false prophesies. It is a dangerous world we live in. Get in the Word and study truth and the lies will be easier to spot. Keep truth ahead of your emotions or you can get wrapped up and carried away by every wind of doctrine and sleight of hand of man. Allow the Spirit to do His calling to lead us into all truth. If anyone teaches anything else, then as Paul said let him be accursed. Maranatha!