I was given a offer from a job, start date, background clear.

I was offered a position at a new company, waited until back ground came back to give two weeks at current employer. I was told 2 dayss after I gave my 2 weeks that they made a mistake and start date will change, they have to see what the issue is. I was told to wait until the following Weds to either delay my two weeks or cancel it all together. I received a call on the following Tues by the store manager stating "what day was I told to start on the offer letter after the background cleared" I told him April 18th, He informed me to come in on that date stated on the paperwork. On the morning of April 18th the store manager called me and told me not to come in, that the background was put on hold??. I informed him I already did my last day the prior Thursday, I have no job now, he stated that it was something that probably will be cleared up in a few days. I get the call April 21st stating that they aren't going to move foward