diff --git a/src/lib.rs b/src/lib.rs
index 8329daa..1617878 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -662,6 +662,32 @@ impl Client {
         to: &chrono::NaiveDate,
         department: Option<i32>,
     ) -> Result<Vec<RpcSubstitution>> {
+        dbg!(
+            reqwest::Client::new()
+                .get(self.rpc_url.as_str())
+                .header(reqwest::header::USER_AGENT, &self.user_agent)
+                .header(reqwest::header::CONTENT_TYPE, "application/json")
+                .header(reqwest::header::ACCEPT, "application/json")
+                .header(
+                    reqwest::header::COOKIE,
+                    self.session.as_ref().context("Not logged in")?,
+                )
+                .json(&json!({
+                    "id": "ID",
+                    "method": "getSubstitutions",
+                    "params": {
+                        "startDate": serialize_date(*from),
+                        "endDate": serialize_date(*to),
+                        "departmentId": department.map_or(0, |d| d)
+                    },
+                    "jsonrpc": "2.0"
+                }))
+                .send()
+                .await?
+                .text()
+                .await?
+        );
+
         let resp: RpcResponse<Vec<RpcSubstitution>> = reqwest::Client::new()
             .get(self.rpc_url.as_str())
             .header(reqwest::header::USER_AGENT, &self.user_agent)