Chau form

カルピスは、遅くなっちゃう
でもちゃんと送るね

Like in this sentence for example. I've come across chau loads of times but I've never actually understood what it means. Also I've never understood chanto. It just means neatly in this sentence?

"...chau" is a colloquial form of "(....te) shimau," a verb ending to mean that "something unfortunately/unexpectedly happens," or without much meaning to make the whole expression somewhat light-hearted in tone. If you have a grammar book, check on "...te shimau" expression.

"chanto" in this case means "I'll BE SURE to send it" or "I'll DEFINITELY send it" or "I WILL NOT MISS sending it." In other instances it can mean "neatly," but in this case it's a bit different.