Boundary conduction mode flyback converter not working

Hello,
We had some 230VAC, 30W T8 LED tubes made for us in China. A number of them have started flashing on and off. A quick flash, then 800ms delay, repeated.
When I took one apart, I found what was obviously an isolated Boundary conduction mode flyback driver. It was obviously BCM because there was an 18k resistor connected from the AC side of the auxiliary coil diode, to a pin on the controller.. (obviously the ZCD pin)
When I removed this 18k resistor, the LEDs stopped flashing and lit continuously, however, with no ZCD pin input, the controller is a bit “Lost”. In fact, it severely overpowers the LEDs, and gives out 45W at just 70VAC input. –Goodness knows how much power it would try and give out if I turned the VAC input any higher than 70VAC.
The Boundary conduction mode flyback controller is an 8 pin SOIC, with the number “AGB2ZA” on it.

I cannot find the datasheet anywhere on the web, -do you know where is the datasheet?

In my opinion it looks like output under voltage protection tripping in.
Try to mess with voltage divider going to feedback pin (I assume it is primary side regulation).

Thanks, theres no divider...just the 18k resistor going from the AC side of the auxiliary coil diode straight into the controller.
Thats the only feedback from the secondary to the controller, theres no opto.