Error calling a contract method

[nicosampler]

I'm having this error:

Failed to parse the request body: No case matched:
  At /kind, unexpected string instead of endorsement
  At /kind, unexpected string instead of seed_nonce_revelation
  At /kind, unexpected string instead of double_endorsement_evidence
  At /kind, unexpected string instead of double_baking_evidence
  At /kind, unexpected string instead of activate_account
  At /kind, unexpected string instead of proposals
  At /kind, unexpected string instead of ballot
  At /kind, unexpected string instead of reveal
  Unhandled error (Invalid_argument "Z.of_substring_base: invalid digit")
  At /kind, unexpected string instead of origination
  At /kind, unexpected string instead of delegation

Trying to call a contract method:

function main(const action: entry_action; var finance_storage: finance_storage): (list(operation) * finance_storage) is
  block {
    skip
  } with case action of
    | Deposit(param) -> depositImp(finance_storage)
    | Withdraw(param) -> withdrawImp(finance_storage)
    end;  

compiled code

parameter (or (unit %deposit) (unit %withdraw)) ;

I'm making the call like so:

  const v3FullPoolAddress = "KT1EufKiVMbL6r4T2whQT88crUZJM7J3SW66";
  const bobKeys = {
    pk: "edpktvrjBvRB7zJGEQKBFpwGS2rb12VD4ibTv7Kqgv9yAi6ARW3vQy",
    sk: "edsk3k86EP8oqGfgpmVq5XPpjwJTb3ivmDUpZw12j13dvnqnU3PCnM",
    phk: "tz1P4iVZLrBEjqNKUDBe7bqV8CB2AQ51ZKf8"
  };

  eztz.contract
    .send(v3FullPoolAddress, bobKeys.phk, bobKeys, 100, "(Left Unit)", 0.5)
    .then(res => {
      console.log(`Deposit Call from bob ${JSON.stringify(res)}`);
    })
    .catch(console.log);

calling the contract using tezos-client works fine, any idea what can I be doing wrong?