Payment for no goods

I requested a 6V coil for my vehicle and was told they have an item but I must pay in advance before they can process this order. This I did on 3rd of April, 2018 and was informed that delivery would be by 5th April, however this did not arrive and on Friday 6th was informed that this had arrived but was not the correct item and they did not have another to supply. I asked them to refund my payment and confirm but this has not happened despite having sent several emails requesting this refund and I have had no response to my emails. Please assist to inform others who may also be caught by this situation.