Didnt Get Paid My Approved Pto On 2 Paychecks

Fl, 28m,

I work an awful schedule, paid every week schedule is wednesday->tuesday (meaning tuesday is my pay periods friday)

Anyway i had requested PTO weeks ago, and it got approved, i have proof of this as i have a copy of the PTO approval, with mine and MGMT signatures. The dates of the PTO days were nov18, nov 20/21. My total hours worked those week (including the PTO) wouldve been 56hours on week 1 and 40 hours total on week 2

The 18th was 8hours on 1 paycheck, and the 20/21st was 16 hours on the second paycheck.(8 hours is the max we can pto for each day, even tho we work 12 hour shifts)

Last week i received a check that felt a bit light and thought it mightve just been taxes eating an extra $150, this week i received less than half a paycheck and decided something was DEFINITELY abnormal, when i check both pay statements i wasnt ever granted the approved PTO hours

When i contacted my boss he said “i dont remember approving any pto hours” so i sent him my approval he had signed, and asked how many hours i can expect to receive on the next check and i keep getting the answer “i dont know ill have to check with HR and see how many hours they will approve”

What is my course of action for this?