BLAIRSVILLE, Ga. — The Union County Sheriff’s Office is warning residents not to call phone numbers that appear in pop-up messages claiming a computer, tablet or other device has been infected, hacked or compromised. The office said the alerts often look convincing and urge people to call a listed number immediately for technical support. Officials said those messages are a common tactic used by scammers. Legitimate technology companies generally do not use random pop-ups to