What exactly did they return? Did they return your application? Why?
Do you meet the residency requirements?
If you meet the requirements, you can leave Canada and get a travel document when you want to return. However, the processing time for a travel document can be a few weeks at some embassies so if you are not going to stay for months, you may want to apply for the travel document as soon as you arrive at home so you will have it when you want to go back. A travel document is usually valid for 6 months.