I am graduating this summer and going towards a master's degree. I had an offer with a zero hour contract for a few months with a startup. On the contract, no start/end date is specified, but I did set a start date. Also, the CEO and CTO shown a lot of interest in hiring me, especially since they have no one currently with my skill set.
After signing the contract, my circumstances have changed. It is a combination of the master's degree starting earlier than expected, some relocation and personal issues. This would reduce my availability (I was supposed to work about 15-20 hours per week for about 12 weeks, now it has been reduced to only 4-5 weeks).
The contract has the standard 2 weeks notice, but since it is zero hours, I've been told that I can simply stop taking hours.
What is the best way to proceed with minimal damage? I could go for the 4-5 weeks available and then resign, but I'm afraid this would create a lot of hassle (both for me and the company) and would help no one. On the other hand, explaining upfront what happened might get as unprofessional.
Some clarifications: I've been given a zero hours contract because I couldn't commit to a fixed number of hours per week, but I've been verbally guaranteed at least 16 hours per week, if willing to take them.