Genting theme park pay list

Now I am only in charge of the theme park tickets for:

Me
Su
Choi
Choy
John
Set Hong
Low B
Foong
Kuan Gong
Xue Er
Kok
Shark
Kong Tat Chee
Mr & Mrs Ong

Until today i only receive the money from Su, Set Hong, Low B, Foong, Choy, Choi, Shark & John.
Because of before this i forgot about Mr & Mrs Ong
Thus the payment have a bit changed
The equation:

12*30=360
3*59=177
360+177=537
537/15=36(35.8)

There are 12 tickets with staff price
3 tickets are original price
Thus divided the sum
Each of you have to pay me rm36
Therefore, Low B, Foong & Choi owed me rm3
On the other hand, I owed Su rm6
Set Hong, Choy, Shark & John have settled their payment
Kuan Gong, Xue Er, Kok, Kong Tat Chee and Mr & Mrs Ong haven't pay me
That's all...
Bye