in src/main/scala/com/gu/invoicing/refundErroneousPayment/Impl.scala [98:108]
def applyCreditBalance(invoiceNumber: String, amount: BigDecimal, comment: String): Unit =
Http(s"$zuoraApiHost/v1/object/credit-balance-adjustment")
.header("Authorization", s"Bearer $accessToken")
.header("Content-Type", "application/json")
.postData(s"""
|{
| "Amount": $amount,
| "Comment": "$comment",
| "SourceTransactionNumber": "$invoiceNumber",
| "Type": "Decrease"
|}