diff --git a/src/main/java/ch/ethz/seb/sebserver/webservice/servicelayer/session/impl/SEBClientInstructionServiceImpl.java b/src/main/java/ch/ethz/seb/sebserver/webservice/servicelayer/session/impl/SEBClientInstructionServiceImpl.java
index a8e773c8..5ec6fae1 100644
--- a/src/main/java/ch/ethz/seb/sebserver/webservice/servicelayer/session/impl/SEBClientInstructionServiceImpl.java
+++ b/src/main/java/ch/ethz/seb/sebserver/webservice/servicelayer/session/impl/SEBClientInstructionServiceImpl.java
@@ -167,14 +167,19 @@ public class SEBClientInstructionServiceImpl implements SEBClientInstructionServ
             return null;
         }
 
-        final ClientInstructionRecord clientInstruction = queue.peek();
+        // Remove the head instruction from the queue
+        final ClientInstructionRecord clientInstruction = queue.poll();
         if (clientInstruction == null) {
             return null;
         }
 
         final boolean needsConfirm = BooleanUtils.toBoolean(clientInstruction.getNeedsConfirmation());
-        if (!needsConfirm) {
-            queue.poll();
+        if (needsConfirm) {
+            // add the instruction back to the queue's tail if it need a confirmation
+            queue.add(clientInstruction);
+
+        } else {
+            // otherwise remove it also from the persistent storage
             final Result<Void> delete = this.clientInstructionDAO.delete(clientInstruction.getId());
             if (delete.hasError()) {
                 log.error("Failed to delete SEB client instruction on persistent storage: ", delete.getError());
@@ -221,14 +226,12 @@ public class SEBClientInstructionServiceImpl implements SEBClientInstructionServ
                 return;
             }
 
-            final ClientInstructionRecord instruction = queue.peek();
-            if (String.valueOf(instruction.getId()).equals(String.valueOf(instruction.getId()))) {
-                queue.poll();
-                this.clientInstructionDAO.delete(Long.valueOf(instructionConfirm));
+            final Long instructionId = Long.valueOf(instructionConfirm);
+            if (queue.removeIf(instruction -> instructionId.equals(instruction.getId()))) {
+                this.clientInstructionDAO.delete(instructionId);
             } else {
-                log.warn("SEB instruction confirmation mismatch. Sent instructionConfirm: {} pending instruction: {}",
-                        instructionConfirm,
-                        instruction.getId());
+                log.warn("SEB instruction confirmation mismatch. No pending instruction found for id: {}",
+                        instructionConfirm);
             }
         } catch (final Exception e) {
             log.error(
@@ -261,33 +264,6 @@ public class SEBClientInstructionServiceImpl implements SEBClientInstructionServ
                 .forEach(this::putToCacheIfAbsent));
     }
 
-//    private ClientInstructionRecord chacheInstruction(final ClientInstructionRecord instruction) {
-//
-//
-//
-//        final String connectionToken = instruction.getConnectionToken();
-//        if (this.instructions.containsKey(connectionToken)) {
-//            // check if previous instruction is still valid
-//            final ClientInstructionRecord clientInstructionRecord = this.instructions.get(connectionToken);
-//
-//            System.out.println("************* previous instruction still active: " + clientInstructionRecord);
-//
-//            if (BooleanUtils.toBoolean(BooleanUtils.toBooleanObject(clientInstructionRecord.getNeedsConfirmation()))) {
-//                // check if time is out
-//                final long now = DateTime.now(DateTimeZone.UTC).getMillis();
-//                final Long timestamp = clientInstructionRecord.getTimestamp();
-//                if (timestamp != null && now - timestamp > Constants.MINUTE_IN_MILLIS) {
-//                    // remove old instruction and add new one
-//                    System.out.println("************* remove old instruction and put new: ");
-//                    this.instructions.put(connectionToken, instruction);
-//                }
-//            }
-//        } else {
-//            this.instructions.put(connectionToken, instruction);
-//        }
-//        return instruction;
-//    }
-
     private ClientInstructionRecord putToCacheIfAbsent(final ClientInstructionRecord instruction) {
         final SizedArrayNonBlockingQueue<ClientInstructionRecord> queue = this.instructions.computeIfAbsent(
                 instruction.getConnectionToken(),
@@ -302,8 +278,6 @@ public class SEBClientInstructionServiceImpl implements SEBClientInstructionServ
             log.debug("Put SEB instruction into instruction queue: {}", instruction);
         }
 
-        System.out.println("************* register instruction: " + instruction);
-
         queue.add(instruction);
         return instruction;
     }