There are two reasons for that price increase.
1. You paid initially less because this was the "Promotional pricing for first year".
As written in the terms, which can be found on the pricing table:
Students and teachers: Save 70% off Creative Cloud for a limited time. Hurry, offer ends <DD MONTH YEAR> Introductory Pricing Terms and Conditions A$21.99/month (GST inclusive) Creative Cloud Introductory Pricing - save 70% in the first year *Offer starts on MONTH DAY, YEAR and expires on MONTH DAY, YEAR. Eligible students (aged 13 years and older) and teachers can save 70% off our standard All Apps Adobe® Creative Cloud™ price when they purchase an annual membership to Adobe® Creative Cloud™ at a reduced price of A$21.99/month (GST inclusive) for the first year. At the end of the first year (and each year after that), we will renew your contract automatically for another year at the then-current standard monthly student and teachers price, which will be calculated annually at 40% off our standard All Apps Adobe® Creative Cloud™ price. Your membership will not automatically renew if you cancel your membership prior to the end of any membership year. |
40% off of the "All Apps" plan makes A$43,99.
2. Adobe increased pricing last year, as currency exchange rates have fluctuated significantly over the last few years.
Please see Why did my membership price change? for more informations.