Refund is not happening 6 months later

I placed an order in February. The part was incorrectly advertised on the website so they couldn't fulfill the order. I said okay fine because I understand that mistakes happen, just refund me my money. After contact with numerous people (because you always get put in contact with a new person which is very frustrating), they eventually cancelled the order but still have not refunded my money. It is now the end of August. They are very bad at communication and cannot just action a simple refund.