Wildlife 48 telemetry question

Just wait mud it will happen.... I had two on my collars stop tracking just this weekend. Saturday my top dog was 800 yards and headed towards us in a round about way, she was running a hog and had just been a couple of miles from us when all the sudden i loose her. I was able to pin point her with my wild life and started calling her off from the direction she was at. The garmin finally picked her collar back up when she got fifty yards from me. One of mikes prize pups had the same thing happen saturday. Sunday my second best dog had her garmin collar stop tracking at 746 yards when she was running a hog and it didnt pic her back up until i got within 50 yards of her. I dont know what causes the garmins to fail but it IS a problem. I was not tracking for at least two hours and with a dog like her she could have been miles away from us. So from here on out my mutts will have a wildlife or some sort of back up telemetry collar on. Both of the garmin collars were under three months old that failed this weekend.