If you contributed to a crowdloan and ended up with a balance of zero when you expected to have some balance close to 1 DOT, your account most likely was reaped (deactivated) and the remaining funds were burned. You can read more about what this means here.

How to check if that's what happened

1. Go to a block explorer and enter your address. In the following examples we used Subscan. Other block explorers will have different layout.

2. In the extrinsics tab look for your contribution. It will be a "crowdloan(contribute)" or a "utility(batch_all)" extrinsic

3. Click on the Extrinsic ID. This will open up the details of that extrinsic

4. Scroll down to events and look for an event named "balances(DustLost)". If this event exists, then some balance was lost due to the account being reaped. Click on the arrow to expand it.

5. Next to "Balance" is the amount that was lost when the account was reaped.

How did this happen?

This can happen under a few circumstances:

1. The amount you planned to leave in your account after the contribution was less than 1 DOT.

2. The amount you planned to leave in your account was exactly 1 DOT. In that case it was the fees for the transaction that brought the balance below the existential deposit and led to your account being reaped. 

3. You planned to contribute your entire balance but overestimated the fees. In that case anything that wasn't used up by the transaction fees was burned, but the loss in that case should be minimal.

What can I do?

There is nothing that can be done to recover this amount unfortunately. It is burned and lost forever. 

If you want to learn how to prevent this from happening in the future, please check this article and our Crowdloans FAQ.