The Tithing Question

I have a question about tithing. Not really, but play along and humor me. If the OT is done away with as some will have you think. Why are churches asking for money every Sunday. Why isn't tithing mentioned in the NT except for one little obscure verse in the book of Hebrews. I love Malachi 3:10, the problem is people haven't read the entire chapter. Who was the author speaking too? Lastly, why didn't the Messiah accept the tithe and in conclusion, who acts as the Levites in our current age of dispensation?