Hmmm is guess this is two different issues.
1. Define "failed". Is it not working at all? No power, grinding, running but no water is coming through, etc.
2. Water leveling not maintaining is normally a seal ring. It may just need to be cleaned in most cases. Push the flusher down and use soap and water on a toilet brush. Don't put the entire brush head in the hole, right at the seal is where it needs to be cleaned. 99% of the time this will take care of it.