There are SO many variables to this. Mainly, the terms put forth in the lease and the laws of the jurisdiction that you live in. I am a landlord, and it can be a real pain in the ass sometimes. It's a fine line you have walk between being and asshole and staying profitable vs. keeping your tenants happy and doing the "right" thing.
Fortunately, I am handy and do most repairs/preventive maintenance myself and one of my best friends is a plumber. But there have been times when he was not available where I just used a local plumber - it cost more, but I own my properties free and clear so I don't have a cash-flow issue to worry about (no mortgage, just yearly property taxes and insurance).
Your landlord may not be in the same boat and may have a cash-flow issue. Regardless, three days is too fucking long. Definitely a dick move by the landlord.
That said, the cost of 'lawyering up' would probably exceed the cost of a new toilet!
My advice would be to shit in a bucket until it is fixed through the proper channels. Or pay for it yourself if it is that intolerable. But don't expect the landlord to reimburse you and if you pull any shenanigans like deducting it from the rent or whatever with out his WRITTEN agreement, you are opening yourself up to all the nasty parts of his lease...