Ton M.,

You deserve a response whether it is the answer you desire or not so you can move on.
Does the store, district or region have a Director of Human Resources?
If this letter does not get what you think is a timely response I suggest that you contact the store manager and ask for a meeting to be attended by you, him/her and an H/R Rep for the company. At this point you should be looking for a cut and dry answer as to a future schedule or not.
Keep in mind the economy is in the tank and what they sell and the services they offer for some might be a luxury and thus lower business levels.
Hope this helps.
Stop back and let us know how it pans out.
BillR.