Dishonesty towards the customer

I had a internet contract with them and now the contract has expired the router is still locked and it was not mentioned when I took the contract with them. It is unfair to me because It should have been my router at the end of of the term I previously had a contract with other services provider and at the end of of the contract the router was mine and I used it with any service provider that i wanted to. Multichoice is taking us for a ride by refusing to unlock my router.