Help me and earn 10 pts please.?

i would like to write complaint letter with our payroll manager, they deduct my salary. i went for vacation and before i go i received my salary which according to them they gave me transportation allowance. now i came back for vacation and they deducted my salary bec accrding to them they shouldn't gave me transportation allowance beacuse i did not utilize it during my vacation. i did not receive transportation allowance that time i received my early pay so how come they're saying i was given trans allowance. help me to compose complaint letter regarding this matter please.