How to unset array key

I have been trying to remove an item from an array, but it wont work at all, it just does nothing.

PHP:

foreach($this->ah->getAll() as $key){
        //if($key == $aucid){
    
            $money = EconomyAPI::getInstance()->myMoney($player);
            $sellname = $key["seller"];
            $seller = $this->getPlugin()->getServer()->getPlayer($sellname);
            $price = $key["price"];
            $lore2 = $key["lore"];
            $nbtencoded = $key["item"]["nbt_b64"];
            $newnbt = base64_decode($nbtencoded);
            
            $itemclicked->removeNamedTagEntry("auction id");
            $itemclicked->setLore($lore2);
            $money2 = EconomyAPI::getInstance()->myMoney($seller);
            if($money < $price){
                $player->sendMessage($this->getPlugin()->getError("Uh oh, you need more money to purchase this item"));
                return false;
            }

            if($seller == $player){
                $player->sendMessage($this->getPlugin()->getSuccess("Item removed"));
                $player->getInventory()->addItem($itemclicked);
                unset($this->ah->getAll()[$aucid]);
                $this->ah->save();
                $this->menu->getInventory()->close($player);
                return true;

 

1. $aucid is not defined
2. To remove a key use $config->remove($key)