AppliancePro's Lack of Service

I used this company to repair and regas my fridge. They sent a technician within about 24 hours and the fridge worked O.K. for two or three weeks, then stopped cooling effectively. AppliandPro's invoice is clearly marked "6 months guarantee", so I contacted them to come back. Despite three phone calls and three SMS's over the past 10 days nobody has come back to me and the fridge remains out of order.