Found 'TEXT' but Expected 'NUMBER' for the function 'get'at lineNumber 9

Found 'TEXT' but Expected 'NUMBER' for the function 'get'at lineNumber 9

Hello,

I am getting this error:

Found 'TEXT' but Expected 'NUMBER' for the function 'get'at lineNumber 9

With this formula to add the total value of sales (deals module) into a customer field

Email = Email.toString();
resp = zoho.crm.searchRecords("Deals","Email");
info resp;
total = 0.0;
for each  rec in resp
{
stage = rec.get("Stage").toLowerCase();
if(stage.contains("Closed Won"))
{
total = total + rec.get("Amount").toDecimal();
}
}
updateResp = zoho.crm.updateRecord("Contacts",Email,{PurchaseOrderSum:total});

How can I fix it?

Thanks