Mango acts like it is rectifying, but it is not

Flight was delayed&notified by sms with no explanation on reason or when to check in.I called&was advised to check in at the original time.There were earlier flights, but they would not put me on an earlier flight even though I presented at check in counters in time to check in for that flight.I received a meal voucher,which was not accepted in boarding gates section.I waited two and a half hours to board without an explanation of why it was delayed.I tried to use the voucher in the aircraft to purchase water, but they did not accept it either.I was left tired,thirsty&late for my transport from the airport. I'm very disappointed with the delay,lack of communication&lack of options provided to me. I could have waited with my family for the flight, if they told me I would only leave in>5 hours time since I called.I was sms'd to call in for a voucher,but prefer that this be provided without me needing to call. It is only valid for 3 months from receipt.I'm not planning to fly Mango within 3months.Both vouchers had no value unless provided in a way I can actually use them.It's frustrating-Mango acts like it is rectifying, but it is not&I am more frustrated as the vouchers are useless.