Decision not received after 6 months. Is this normal?

As the title suggests, I applied back at the start of September, and it is now March without a decision back. I've emailed and called their office and they have confirmed that they have my application, but would not provide any progress on what's going on or if I needed anything.

I'm a little confused as to why I haven't received a decision yet, considering that all my other classmates and friends have gotten a decision back within 2 months.

Should I be concerned?