Inefficient ordering process with Zasttra

I placed my order with Zasttra on 08 Sept 2018 I queried about the delivery of my order to receive the response on 28 Jan 2019 that that they had lost track of the order. I had the choice of them returning my funds or reordering the product. I chose the latter. On 29 Jan 2019, Zasttra informed me that they had issued a voucher to the value of my undelivered purchase. When I attempted to buy the same product, I was expected to pay for delivery again. Considering that I’d already paid delivery, I considered it unacceptable to pay for delivery twice. I informed Zasttra on 03 Feb 2019. On 10 Feb 2019 Shaun Parker responded by telling me how to use the voucher allocated to me but failed to address my complaint. I submitted my complaint again and received another response from Shaun Parker on 06 April 2019. Once again he failed to address my complaint. I decided that I have been more than reasonably patient with Zasttra and no longer wish to proceed with the order. I want a refund.