c# tag = "newtag" isn't working

Like it says in the title im setting a new tag with tag = “newtag” but it keeps its old tag. I checked twice the new tag does exist.

void Update()
{
if (tag == “DoMeshTopLeft”);
{
GetComponent().mesh = CrateMeshChunk();
GetComponent().mesh = CrateMeshChunk();
}
StartCoroutine (StretchMethod());
if (tag == “DontMeshTopLeft”)
{
GetComponent().mesh = CrateMeshChunkDontMeshTopLeft();
GetComponent().mesh = CrateMeshChunkDontMeshTopLeft();
}
}

In the above code StartCoroutine is called in update,it has called multiple times before executing the return of yeild statement of StartCoroutine.Instead of StartCoroutine use invoke() or StretchMethod().

void Update()
     {
         if (tag == "DoMeshTopLeft");
         {
             GetComponent<MeshFilter>().mesh = CrateMeshChunk();
             GetComponent<MeshCollider>().mesh = CrateMeshChunk();
         }
         Invoke("StretchMethod", 2);
//        StretchMethod();
         if (tag == "DontMeshTopLeft")
         {
             GetComponent<MeshFilter>().mesh = CrateMeshChunkDontMeshTopLeft();
             GetComponent<MeshCollider>().mesh = CrateMeshChunkDontMeshTopLeft();
         }
     }