Why am I only paid for 3 days when I watched a dog for 4?

The charges would be as follows: 6/22 - 6/23 = 1 night 6/23 - 6/24 = 1 night 6/24 - 6/25 = 1 night

Therefore you should have been paid for 3 nights. The clock starts upon arrival and stops upon departure and is for a 24-hour period. Rover fees are deducted from your gross earnings. Therefore, the amount you are actually paid is gross - Rover fees.