anyone else have a contract lost to another investor?

[Account Closed]

I did my first deal and got the contract and took it to escrow. This was a pre-forclosure so in CO the homeowner has 3 days to cancel. While I was getting the contract signed another investor door knocked the house. When the homeowner told me he was going to cancel the contract I went to his house to ask why and pick up his cancellation. He wasn't there and stopped answering my phone calls and texts. While I was there I saw 2 other investors driving by slowly and staring at me. What can  I do in the future to avoid this? Or is this apart of preforclosures to where I can get a contract and hope to close everytime?