Alarm fault

Hi, having problems with the alarm on my 2003 renault megane it's a 1.6 Fiji. The car wouldn't start the other morning & then when I went back to it in the afternoon the alarm started as soon as you opened the doors. Figured the battery was flat so had the battery charged & the car started & drove fine just with the alarm blaring & the hazards going off. In the end I called out the rac & they guy disconnected the alarm siren & had said that would stop the alarm from working, it stopped the noise but the hazards were still flashing (didn't notice til after he left. He said it could be a problem with the ecu? Obviously I can't drive around with the hazards flashing but can't make them stop. They aren't going off as soon as you open the door now it's now as soon as you put the key in the ignition. If anyone can suggest anything I'd be grateful. Thanks

Alarm fault