diff --git a/package.json b/package.json
index 4c7ed06..1c5baa1 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@tornado/tornado-oracles",
-  "version": "3.2.1",
+  "version": "3.3.0",
   "description": "Oracles for Tornado-specific transactions & actions",
   "main": "./lib/index.js",
   "types": "./lib/index.d.ts",
@@ -11,7 +11,8 @@
     "prettier:fix": "prettier --write . --config .prettierrc",
     "build:abi": "yarn typechain --target ethers-v5  --out-dir src/contracts ./abis/*.abi.json",
     "test": "echo \"Error: no test specified\" && exit 1",
-    "prepare": "npm run build && npm run build:esm"
+    "prepare": "npm run build && npm run build:esm",
+    "prepublish": "npm run prettier:fix"
   },
   "repository": {
     "type": "git",
diff --git a/src/feeOracle.ts b/src/feeOracle.ts
index 5b15fdc..e8c9019 100644
--- a/src/feeOracle.ts
+++ b/src/feeOracle.ts
@@ -18,6 +18,7 @@ import { ChainId, defaultGasPrices, defaultInstanceTokensGasLimit, InstanceToken
 import { bump, calculateGasPriceInWei, convertETHToToken, fromGweiToWeiHex, serializeTx } from './utils';
 import { getOptimismL1FeeOracle } from './contracts/factories';
 import { GetWithdrawalFeeViaRelayerInput } from './types';
+import { AvailableTokenSymbols } from '@tornado/tornado-config';
 
 export abstract class TornadoFeeOracle implements ITornadoFeeOracle {
   protected provider: JsonRpcProvider;
@@ -163,6 +164,18 @@ export abstract class TornadoFeeOracle implements ITornadoFeeOracle {
    * @returns {HexadecimalStringifiedNumber} Refund amount in WEI (in hex format)
    */
   calculateRefundInETH(gasPrice: BigNumberish, tokenSymbol: InstanceTokenSymbol): HexadecimalStringifiedNumber {
+    // Refund only available for non-native tokens on Ethereum Mainnet and Goerli
+    if (![ChainId.MAINNET, ChainId.GOERLI].includes(this.chainId) || (tokenSymbol as AvailableTokenSymbols) === 'eth')
+      return '0';
+
+    // Notify user about error if incorrect token symbol provided
+    if (!Object.values(InstanceTokenSymbol).includes(tokenSymbol)) {
+      console.error(
+        `Invalid token symbol: ${tokenSymbol}, must be lowercase token from one of Tornado ETH Mainnet pools`,
+      );
+      return '0';
+    }
+
     // In Tornado we need to calculate refund only on user side, relayer get refund value in proof
     const gasLimit = defaultInstanceTokensGasLimit[tokenSymbol];
     return BigNumber.from(gasPrice).mul(gasLimit).mul(2).toHexString();
@@ -232,22 +245,18 @@ export abstract class TornadoFeeOracle implements ITornadoFeeOracle {
    *
    * @returns {Promise<HexadecimalStringifiedNumber>} Fee in WEI (hexed string)
    */
-  async calculateWithdrawalFeeViaRelayer(
-    params: GetWithdrawalFeeViaRelayerInput,
-  ): Promise<HexadecimalStringifiedNumber> {
-    let {
-      tx,
-      txType,
-      relayerFeePercent,
-      currency,
-      amount,
-      decimals,
-      refundInEth,
-      tokenPriceInEth,
-      predefinedGasLimit,
-      predefinedGasPrice,
-    } = params;
-
+  async calculateWithdrawalFeeViaRelayer({
+    tx,
+    txType,
+    relayerFeePercent,
+    currency,
+    amount,
+    decimals,
+    refundInEth,
+    tokenPriceInEth,
+    predefinedGasLimit,
+    predefinedGasPrice,
+  }: GetWithdrawalFeeViaRelayerInput): Promise<HexadecimalStringifiedNumber> {
     const relayerFee = this.calculateRelayerFeeInWei(relayerFeePercent, amount, decimals);
     const { gasPrice, gasLimit } = await this.getGasParams({ tx, txType, predefinedGasLimit, predefinedGasPrice });
     const gasCosts = BigNumber.from(gasPrice).mul(gasLimit);