Has been vs. Have been

Hi, I am a bit confused with when to use "has been" vs. "have been" when it is followed by "there". The confusion only started when microsoft auto corrected my sentence. Since i'm no grammar expert, i accepted the "change" word suggested.

Here is the sentence:

Since your arrival, there have been several conversations about your behavior.

Word suggestion:

Since your arrival, there has been several conversations about your behavior.

Thanks in advance.