Ultimately, tenants can and usually will make it very difficult for a landlord to show the property unless they have an incentive (usually financial) to do so. Hopefully the lease agreement specifically spells out when the home can be shown, who can show it and under what terms it can be shown. You might also review the landlord / tenant laws of your state which should be fairly easy to access online.
Sorry to hear you are having problems. I would suggest contacting a lawyer regarding your questions.
Or, set up a time to meet with a REALTOR. There are a lot of questions and answers they would need to ask you further regarding what is happening.
Hope this helps!
Broker Sales Associate
Coldwell Banker Chris Kutzkey REALTORS