-   function passThruGate(uint index, address) override external payable {
+  function passThruGate(uint index, address payer) override external payable {
        uint price = getCost(index);
        require(msg.value >= price, 'Please send more ETH');

        // bump up the price
        Gate storage gate = gates[index];
        // multiply by the price increase factor
        gate.lastPrice = (price * gate.priceIncreaseFactor) / gate.priceIncreaseDenominator;
        // move up the reference
        gate.lastPurchaseBlock = block.number;

        // pass thru the ether
        if (msg.value > 0) {
            // use .call so we can send to contracts, for example gnosis safe, re-entrance is not a threat here
-           (bool sent, bytes memory data) = gate.beneficiary.call{value: msg.value}("");
+          (bool sent, bytes memory data) = gate.beneficiary.call{value: price}("");
            require(sent, 'ETH transfer failed');
        }
+      if (msg.value - price > 0){ 
+         (bool sent, bytes memory data) = payer.call{value: msg.value - price}("");
+          require(sent, 'ETH transfer failed');}
    }
