Paid hiring bonus without signing agreement then terminated. [SK]

I am located in Saskatchewan, Canada. I was hired in October to work for a surgeon and was told there was no employment agreement to.

Fast forward to December 19th, I am handed an employee agreement to sign with a clause stating that upon signing and execution I will receive a $185.00 bonus. There is another clause stating that by signing I agree that I have received enough time to obtain legal advice for this agreement.

I took it home, read it, and realized that there are multiple things clauses in this agreement that do not align with what has been discussed at time of hire, including one that states the employer is under no obligation to EVER provide the employee a raise and keep track of my bathroom breaks as that would count as time not paid. There is also another section in the agreement that prohibits me from suing should I be terminated and that termination be deemed unlawful. I did not sign it as I wanted to discuss.

The next day when I got paid at 7pm (that's the other thing I never knew exactly when I was going to get paid, once it came at 10pm), I noticed that they had paid me the hiring bonus. In the "termination" section in the agreement nowhere does it state I need to pay back the signing bonus for any reason.

Fast forward to Monday. They ask why I haven't signed the agreement, I bring up my reasons. At the end of the day, I am presented with a termination letter. In the termination letter it states that all outstanding wages will be paid to me in full, however does not say anything about the signing bonus they had paid to me.

I was told that I can expect my final paycheck December 27th. Can they hold back the 185.00 hiring bonus? They paid it to me without me signing the employee agreement.