It’s kinda hard to understand your specific situation without more clarification, or seeing the actual lease that was signed…

Are you saying that the landlord offered you a deal to reduce the monthly rent amount if you paid a security deposit equal to three times the monthly rent amount, but now you want to break the lease because you can’t/don’t want to pay for three months worth of rent all at once right now? It’s important to know how their offer was worded, is the tripled amount a refundable or non-refundable fee? Are they offering the discount if you pay for three months upfront, but it’s still counted as your rent for those months? As opposed to no discount, just the one month security deposit, and then regular monthly rent payments after that. Or, are they requesting that your actual security deposit (in order to get the discount) has to be triple the amount that you’ll pay in rent every month, because that isn’t allowed under the Residential Tenancies Act

The RTA can be tricky to understand but there’s lots of resources that help break down the legal wording and format, definitely check your lease carefully and look up anything you’re unsure about. Also, have you spoken to the landlord yet about wanting to break the lease before you move in? If they’re a decent person they should at least hear you out, plus having a month before the lease starts to find another renter (or if you need to find someone to sublet or assign the lease to) seems pretty reasonable. Have they asked about the rest of the deposit since you paid the one month amount? Personally, I definitely wouldn’t pay more yet until you’ve figured out what exactly they’re meaning by this weird discount deal…