You are still permanent residents of Canada. However, you are in breach of the residency requirement and thus it is VERY likely if you attempt to obtain a travel document for Canada, you will be refused, which terminates your permanent residency. If you are from a visa exempt country and show up at the POE, they will likely report you for the residency breach, which will lead to a removal order. Once the removal order is executed, you will cease to be a permanent resident of Canada. Note: they cannot refuse you entry into Canada, even if you are in breach of the residency requirement. See ENF 4 Port of Entry Examinations, as it explains this.
If you are admitted to Canada without a report being made or a removal order being submitted and you remain in Canada, once you have 730 days in country apply for new PR cards (the rule is that they look back 5 years from the date of the application, so even if you were in breach, the breach is cured.)
Once you are a foreign national, you may apply again for permanent residency.
The current government has really cracked down on permanent residents in breach of the residency requirement. Some people still report success at arguing H&C grounds at the POE, but I would not count on this working for you.
The "safest" way to do this is to request a travel document. This will be refused, at which point you will no longer be a permanent resident of Canada. You may then apply again. The "risky" way to do this is to simply travel to Canada and attempt to enter the country. You may be served with a removal order, in which case you can appeal it (and argue H&C reasons, although with a 7 year absence I'd be surprised if that was persuasive) or you can leave and then apply for permanent residency again. If you are not served with a removal order, you should be prepared to remain in Canada for at least 730 days, in which case you no longer be in breach of the residency requirement and can apply for a new PR card.
Good luck!