Instalment payment plan

We purchased an oven before we move in new house from a private company that allows to pay instalment. When we move in, so many things happen and we forget about the payment. Total up to only 5x payment. Like few months later, they message to ask about payment. We apologize and we paid the subsequent month and the following month. So we paid twice, left with 3 payments. The first payment, I asked for receipts but took very long. When asked, the person said she is no longer working in that company but is able to help with the payment. We gave benefit of doubt and still transfer second time. The second time, the person ignored me. Until now 1 year later they never find us. We try to call company say someone will contact back but never. If u were to be me, what would u do?