Will not drain water

This washer was full of water when I arrived and wouldn’t drain. I vacuumed out the water and opened the
pump trap to make sure it was clear. I did not find a tech sheet inside and have never seen this model before. Model tag has blank. After serial number and tag says make in China. Filled machine, drained, and it went into spin so I buttoned it up and left. Few hours later and said it was full of water again.