What happens if I don't pay full payment in 1 month?

If I choose my plan to pay it back in 1 month and I do not pay in full within the month, does my plan automatically change to 3 month with 0%? How does this work?

Hi. If you do not select a plan or actively select 1 month then if you do not pay the bill then you will be charged interest on the whole bill and potentially a late payment fee (not sure if they actually charge that)

There is no automatic move to 3 months.

Hi @rjay Welcome to the community. By default all transactions you make are on a 1 month plan, which depending on when you make them can means that you could have to pay it in full in about 10 days (all transactions made up to the 25th need to be paid by the 7th of the next month).
Failure to pay all due on a Monthly Bill (you have up till the end of the calendar month to change plans) means you are breathing the terms of your contract and could be reported to CRAs as well as incur charges and Fees. For more details of billing cycle see: https://tymit.zendesk.com/hc/en-gb/articles/360016949218-What-s-the-billing-cycle-at-Tymit-and-how-does-billing-work-#:~:text=You%20are%20expected%20to%20pay,7th%20of%20every%20month.

The best thing to so is to change all transactions immediately they are made to a 3 month plan, and then at the end of the month you can either pay whatever is due, or make extra payment depending on your cask available.

So if I change it to 3 month plan and then say i pay in full within 1 month I wouldn’t need to pay anything after that?

Correct, you will still get a bill but the money you already paid will be credited to it, so nothing to be paid.