I have an ACT of 23 (24 E, 28 M, 18 R, 22 S, 22 W) and 1890 on sat (560 R, 770 M, 560 W). I saw that my sat is similar to a 28 on ACT and actually my SAT Read/Math score 1330 which is aprox 30 act. So I was planning doing the ACT on Dec but I saw that I did better in the SAT. I was thinking of not sending ACT, not making the ACT on December and erasing my ACT of all applications. Would universities get to know ? 
or should I sent my act scores? Also I was thinking of not sending my bad sat scores would universities get to know if I do not send them, first I got a 1500s in my SAT I improve alot. I hope universities see me and think I did a lot of work or may be it will look bad.
Just send the SAT. No biggie. Only some of the more prestigious schools ask for all your scores from all your tests. But, for the others, just send them what you want them to see.
I’m assuming you didn’t already send the score to some schools? If you already sent scores then I don’t believe you can ‘un-send’ them.
No I haven’t sent any score yet, I am in the process for UC’s that’s why I do not know what to sent. I received my sat result few days ago and it really changed my college list a lot.