Tixsa - Poor service

School made use of Tixsa to manage ticket sales for an event. Tried to buy ticket on 6 September 2018. SMS message confirmed that transaction happened but no ticket was issued. Reported the matter to Tixsa on the morning of 7 September 2018. They requested proof of payment from the bank. Transaction remained pending and could not verify immediately. Eventually confirmed that the transaction was on the bank statement. Sent proof to Tixsa. No response. Started fresh query on 22 October 2018 and was informed that their system showed that ticket was sent. Contested the statement. No response. Refreshed query on 29 October 2018 - no response apart from automated message telling me how important I am as client and that I could expect someone to contact me within 12 hours.