Sonic devices are unlikely to get rid of an established infestation, although they may well discourage a passing visitor from staying. I had a couple of caged pet rats "to stay" recently and I forgot to unplug the rodent deterrent initially - the rats were not in the slightest bothered.
You can have a go with human traps, put them along the edges of rooms, bait with chocolate spread or peanut butter. When you catch one, you have to take it well well away (?miles) before releasing. If they are well established, expect to catch 30 or more.
I used B&Q electric traps, which are claimed to kill them instantly and humanely, and you don't have the problem of hidden rotting bodies you may get with poisoning.
Ultimately though, you may have to put down poison to get rid of them.
Finally, you need to find out where they are getting in, often more difficult than it sounds since a hole the mere size of a pencil is big enough. If you can't, then consider yourself permanently at risk, and leave humane traps or poison down long-term.
Good luck, it is a real nuisance!