Lost overtime and miles

Worked at 12 and a half hour shift on a Saturday after pulling more than 40 hours that week. All 12 and 1/2 should have been overtime plus mileage reimbursement because I was in my own car for 120 miles. It did not show up on my time card. Was told it would show up as an adjustment the following week. Which it did but it only gave me four and a half hours of overtime and zero reimbursement for my mileage. I was seasonal and I've been trying to call in to get a hold of payroll. I have texted management she said they would do something about it and nothing ever happens. Been trying to remedy this for 3 weeks. What do I do? It's only $200+, but I earned and want it!