I buy Samsung s10 from 128 street 96 Avenue store in Surrey British Columbia and its getting hot when I call store they didn't tell to bring in store for checking or they even didn't tell about 15 days return policy even when I call after 12 days only
When I visit again to store manager argues with me and says I should bring within 15 days
I said your sales person didn't give me information about it still they argue and she (manager) speak liudcand argue.
I don't know what exactly transpired when you went to get the phone at the store but if you were not told about the 15 days satisfaction guarantee by the agent the detail would have been in the paperwork you received after you got the phone.
You can try a factory reset and see if it helps if the phone is still overheating then you still have the 1-year manufactures warranty.
You can send the phone for warranty service through Fido or you can contact Samsung directly, you can find Samsung contact info here.