'else' block executed even after 'if' block finishes execution in OnDataChange()

Android beginner here. This may sound very silly, but I'm having issues with an if-else block that I created in my onDataChange() method in an event listener for a firebase database-reference.

Here's the code for the listener:

requestRef.addValueEventListener(new ValueEventListener() {
                    @Override
                    public void onDataChange(DataSnapshot dataSnapshot) {
                        if(dataSnapshot.exists()){
                            for(DataSnapshot request : dataSnapshot.getChildren()){
                                RequestDetails retrievedDetails = request.getValue(RequestDetails.class);
                                if(retrievedDetails.equals(requestDetails)){
                                    alreadyRequested = true;
//                                    finish();
//                                    startActivity(getIntent());
                                    break;
                                }
                            }
                        }
                        if(!alreadyRequested){
                            //alreadyDisplayed = true;
                            mDatabase.child("Requests").push().setValue(requestDetailsHashMap);
                            Toast.makeText(ParticipantSportOptions.this, "Request Successfully Sent!", Toast.LENGTH_SHORT).show();
//                            finish();
//                            startActivity(getIntent());
                        }
                        else if(alreadyRequested){
                            Toast.makeText(ParticipantSportOptions.this, "Request has already been received!\nPlease wait for approval!",
                                    Toast.LENGTH_SHORT).show();
                            return;
                        }
                    }

                    @Override
                    public void onCancelled(DatabaseError databaseError) {

                    }
                });

This listener is inside the overridden method onClick() for a button. What needs to happen is this - the first time this button is clicked, data (a request) is written into the database. For every subsequent click of the button, I check if the user is attempting to send multiple requests and if so I display the toast and return.

What I observe during run-time is that on the first click of the button, both toast messages are displayed.

Why does this happen?