Just for poops and laughs, start from scratch. Bind Tx/Rx. Now, swap your receiver's channel 1& channel 2 inputs (ESC plugged into ch. 1, and servo plugged into ch. 2). Trims all zeroed out/neutral, and endpoints/dual rates maxed out. Try to calibrate ESC's throttle range using your transmitter's wheel to see if you can get neutral signal.

I have a Radiolink RC3S that has a semi-failed trigger potentiometer after one year of use. The neutral point is basically hit,or miss. Trying to get speed control to go into reverse almost never happens, as well as control of light braking (0~50% braking force) is pretty much non existent. Let's just say my thoughts on Radiolink's quality is not what it used to be.