I paid a Chair and a Razer gigantous V2 but i have nor recieved it

Hello. Last 25 of november i bought a chair and a razer gigantous V2 XXL. I paid 369,98€. I recieved an email some days later from a razer´s worker. They haven´t enougth chairs, so they canceled my order and they returned me only 285,20€ and a gift card of 20€. I recieved a mouse because by free because it was a present for buying the chair. I didn´t recieve de gigantous V2 XXL. I wrote to Razer twice but they didn´t response me. I have to buy a chair because i need it. They will return me the rest of the money? Could you help me please?