hours of availibility

I just started this week at my local Target. First shift went well. The only issue thus far... Starting next week I am scheduled to start 3 hours earlier than my availability calls for. They want me to work till 10:00 P.M on Saturday and back on Sunday at 6:00 A.M!! Is this really what Target...

Some background: I'm a month into my job as a Cashier - the first two weeks I was on the learning plan and only worked 4 hours shifts, with a total of 16 hrs per week. Then, for the past two weeks I've worked 40 hour weeks - with usually 8 hour shifts. When I was hired I checked part time, and...