Terrible service 😡

I initially signed up for a home WiFi contract around 2022 and the consultant advises me that I can cancel it at any time.. Fast forward to 2025, I receive a call from a Mondo agent advising my contract is expiring in Sept25 & I'm due for an upgrade. As the conversion continues, he tells me that I will get a new router and sim. I then ask him what's going to happen to the existing contract/SIM? He continues with the 2nd sign-up but ignores my question.. again I repeat myself and he then advises me that I should call the cancellations department and they will cancel. During the conversation I told him that I am not going to pay for two contracts, little did I know that he signed me up for a new contract regardless. The 2nd device was delivered 2 days after the call with the agent and long story short I was billed for the new contract while the existing one was active. They are now harassing me for pmts which I refuse to pay as the sealed package I returned 2 weeks after it was delivered