Welcome to the community!
Some other community members have noted that you should be able to check the device balance by clicking on Upgrade My Phone (see here). It should then show you the balance owing and the end-date of your contract. Have you had a chance to try that method?
Hope this helps 😀
Find out the full cost of Nexus 4 at Fido when you purchased it. Find out how much money you paid for the N4 up front. The difference is the balance you owe Fido over 24months. divided this value by 24 and you get your monthly tab reduction.
You mentioned your contract started in July, so I guess about 4 months has passed. your remaining balance is the total tab balance you owe minus 4 months.
For example. If I sign up my N4 today at $0, my balance is $450, which equates to $18.75 per months, after 4 months I will owe Fido $375 if I want to end my tab contract.