Yoco taking back our card machine and not paying the money for it

Yoco offered to buy back my card machine after I did not use it at all - they collected the unit and said it takes 14-21 days to review. After the waiting period I asked about my payment and then they first asked me what date it was collected . Now they ignoring all my emails. What a terrible way of dealing with the situation ? They collected the unit now they need to pay us the money they own us - terrible terrible and the least they could have done is communicate with us to tell us what is going on. This is theft and I will be opening a case of theft at the polcice as well.