Why restarting router fixes problem

[#1]

I have a internet connection app running to moniter my internet downtime. Most days the connection is fine. On the occasions the connection is lost it reconnects up to five minutes later without me doing anything. My latest downtime lasted approx 9 hours so I decided to switch off my router for 5 minutes. Switched on router within a minute connection fixed. Why did switching router off and on fix the problem???????? What do I require to receive a stable connection that I pay for?

[#2]

"What do I require to receive a stable connection that I pay for?"

To plug the router into the master socket and have no further "within house" phone wiring connected, at a guess.

Certainly that will help and is worth a try to eliminate the effects of any extension wiring.