Why is the mich in the accusative and not the dative?
Kontaktieren takes the accusative case. "Contact" is an intransitive verb (meaning no direct objects) like "eat" for instance. It helps to think that you're not contacting to me (mir). That sounds wrong in both languages.
Hope this helps!
Contact me as soon as possible?
As soon as possible is so rasch als möglich.
Why is there a sie?
From what I've read before, if its a command, you add the Sie
I still dont get it :(
It is a polite form you use for command/request. "Sie" with capital S is formal you, while lowercase s means she or they.
Why not contact me soon?
Soon means bald.
Contact me soon should be accepted