I WANT MY CONTRACTS CANCELLED!!!!!

So I took out 2 contracts on the 21st of April 2019, 2hrs later when I get home the 2 contracts I took for online classes cannot connect to the laptop, it says no internet access and when my phone is connected it says poor quality. I go back into the store on the 22nd of April 2019 to cancel it but they gave me a new router and said their cancellation department is closed due to the public holiday ( which I understood), I should phone today. I call the store today to cancel and they tell me I cannot cancel it they have to 1st do an investigation on the network in the area and when i call the cancellation department they either drop the call or they do not say anything. So my question is, before selling a contract do they not check network coverage? And since when is a client not allowed to cancel a contract if they are not happy with the service?