When foxes/ coyotes in my area get call shy,I switch things up,I may use as many as 2/3 callers place in different positions,I may have 1 out in front an maybe 1 off to the side or behind me,if fox or coyote hangs up.Also I usually have a bulb sqeeeker on the forearm of gun,Then ifin that all fails its time to break out the lures an scents.Another thing I will add,If your area has a lot of pressure and you know that the guys calling are using e- callers,switch to hand calls,If you don't have any there are some really good call makers on this site,Dave Dunbar,(Yotebuster) made me a few calls to try a few years back,I done really well with them.