Question about Overmax X-Monster 3.0

Hello, I have a disconnection problem with the radio control. With batteries measured at 1.48V on the multimeter, the radio control disconnects every 30 seconds and flashes rapidly and faintly and I have to switch it off and on again all the time. If I put in brand new 1.64V batteries measured with the multimeter, the remote control loses the signal at least 3 or 4 times for a 30-minute play session (the car stops moving, the orange light flashes for a few seconds and then reconnects to the car). It's a real pain and I'm no longer having any fun with this car because of these disconnections. I've tried putting the car's internal aerial upright, I've followed the pairing procedure in the manual, but nothing works, the car disconnects even when it's 1 metre away from me, it's really annoying. Have I come across a faulty product or is the whole series like this? And above all, what more can I do to try and solve the problem?