Terms and conditions of contract not met

I was contacted by mobile talk because my contract was due for an upgrade. The representative told me that they will be extending my current contract by 24 months and I will be receiving a free LTE router. I asked him to confirm that my monthly payment will remain the same and that the router is free and he happily confirmed this. Upon receipt of the router I saw that this was not an upgrade but a new contract where I pay more and get even less data. I asked their call centre to immediately cancel this as this was not the agreed terms. My contract was not cancelled as promised and they deactivated my existing data sim without notice. It is 5 days later and having phoned them again, my data sim is still disconnected. These people give false information when selling contracts and can therefore not be trusted. They are wasting my time and money to solve their ***** up.