Head office does not take customer complaint serious

On the 29th November I've been to steers upon ordering the food I informed the cashier that their chicken burger was very dry as if there was no marinade on the breast as I've been to them just two day before... That evening they gave my saucy burgers it was so disgusting the bun was soaking wet of the sauce the fillet actually slipped out I've never had such disgusting burger in my life to think I've always enjoyed their food but after this its just bad