I have the sentence 早くしないと置いてっちゃいますよ. I think this sentence means "Don't act quickly and you'll be left behind but I'm not sure why ちゃいますよ, which I believe to be ちゃう, is used with the て form. I thought that when you change ~てしまう to ~ちゃう, the て is taken off. I believe that to be what is happening here. Something along the lines of the "unintended action" ちゃう and how it would be regrettable if the person were left behind. If in this sentence something else is happening, then it would be new to me and I'd be happy if someone could explain what's occurring here.
First of all, let us make sure who does what in this sentence because as usual, none of that is mentioned in it.
Listener's action: 早くしない
「と」 is conditional
Speaker's action: 置いてっちゃいます
So, the grammatical subject changes mid-way. The main clause is the second half, so the subject of the sentence as a whole is the unmentioned "I/We".
"If you ~~, I/we will ~~."
「置いてっちゃいます」 is how we colloquially pronounce 「置いて行ってしまいます」. It literally means "I/We will leave you here and go."
Thus, the sentence means:
"If you don't hurry up, I/We will go by leaving you here."
"Hurry up or I/We'll leave you behind!"