Not really sure what you mean by “I have 20”. If you are concerned, doing a factory reset might solve the issue of there is something weird and someone was able to get into your network.
If you never update your router, you should probably start with that. Not using default passwords would also be smart.
TLDR: Clear out any QoS settings or factory reset. Update. Don’t use default passwords
The only reason I can think it would be expensive is if it was a really complicated run. But seems way too much.