I've used two methods, without a contractor, which have worked.
1. Buy a medium size havaheart trap ( if it will fit, or if you have access to, the space they'e in.) This will trap them without harm and you can then remove them to a happier place.
2. This may sound silly, but squirrells hate the smell of moth balls. I had a couple of very brazen ones that got into the eaves where a trap would not fit and they just loved to chatter at me from their high perch...ha ha. I got up there with a box of moth balls and tossed them around their "home" and they were gone in days.