Chomped off down to the stem usually is a sign of hornworms.

Look closely for them at night and dispose of in soapy water and go get some BT K variant for future ones.

Leaf loss is usually a sign of overwatering -- water, deeply, let dry out completely, water deeply and so on is the best way to water peppers. They can also lose them to drought conditions, so if you don't think you're overwatering, then some heavy mulch might help. Overfertilizing can also cause it... what's your feeding schedule and with what?

Kevin

"Have tried the Epsom salt thing."

What "thing" are you talking about?

Rodney