Hey @ liyi !
Oh no, I'm sad to learn you've lost your phone! It's never fun when that happens
Not to worry though, you've got several options to work with
1) you can get a brand new phone at full price with no agreement and keep the agreement you currently have.
2) you can buy out of your current agreement by paying the remaining balance of the phone you lost and then you can get a new subsidized phone with a new agreement.
3) You can buy a 10$ sim card and use it in an old or borrowed phone
Also, did you already block your line through your account on fido.ca? I recommend doing that so that no one can use your service. Don't hesitate to let me know if you need help with that.
Does this help you in the decision-making?