Overdue refund, 2 months+ Holding my money Ransom

I ordered and paid for tiles from Leroy Merlin Fourways in May and they had checked that they have stock and asked that i collect my tiles on the following Wednesday. when the Wednesday came and i went to pick up my order, they claimed to have been out of stock and that a mistake was made in checking inventory. I was promised they will make a special order but they never did. for the past 2 months almost 3, i have been chasing my refund and have been given the run around with regards to my money. I am disgusted with the service and them holding my money ransom.