Why can energy consumption increase if the meter is working?

Good day. Tell me, I started to pay a lot for electricity. Prior to that, he paid up to 250 per month. Now it comes to 800-900. The meter is three-phase, I rarely use a crusher. Mostly small household appliances. Well, refrigerator, TV, and three light bulbs in the house. We came to check from the accounting department, they said the meter works fine. Where can there be losses? And how to check the meter yourself for losses on electrical appliances?