Have you attempted to contact the manufacturer of the chair. If the chair is from a reputable manufacturer, they will have a support number to call or EMAIL.
I have a chair that has a hand control with 8 buttons. As long as the chair is plugged in, the buttons for recline and headrest work. But only one button works at a time. If one of the recline buttons is activated, the headrest buttons do not operate and vice versa. The massage, Heat and Lumbar buttons require a Power Button to be pressed first.
If neither recline button works (Up or Down), it could be a defective control. Do you have access to a second control? Is your control handheld or part of chair
It may be a frayed wire underneath. Check UTube for some help. See attached for frayed wire issue.
recliner electric recline button does not work utube - Bing video