Fix: Replace batteries or buy a new remote or receiver
If the wall switch works but one of the remotes doesn't, check the batteries first. Still nothing? — You may need a new remote. Home centers carry a few models, and you can find a wide selection online.
If you can't find one for your garage door opener model, you can try a universal remote or you can install a new receiver. A receiver replaces the radio frequency the opener uses with its own. An added bonus of a new receiver is that it will automatically update older openers to the new rolling code technology, which stops the bad guys from stealing your code. Just plug the new receiver into an outlet close to the opener, and run the two wires provided to the same terminals the wall switch is connected to