Css bootstrap form Rails 3.2

I would have the form in the left, but i obtained the form in the right:

I really don't know what is the problem. Probably some Css is in contrast with bootstrap. I would have the text-field separated (i obtained everything merged) this is the css of my form:

<div class="container">
    <div class="row">
        <div class="col-sm-12">
            <legend>Mr. Sosa:</legend>
        </div>
        <!-- panel preview -->
        <div class="col-sm-5">
            <h4>Add payment:</h4>
            <div class="panel panel-default">
                <div class="panel-body form-horizontal payment-form">
                    <div class="form-group">
                        <label for="concept" class="col-sm-3 control-label">Concept</label>
                        <div class="col-sm-9">
                            <input type="text" class="form-control" id="concept" name="concept">
                        </div>
                    </div>
                    <div class="form-group">
                        <label for="description" class="col-sm-3 control-label">Description</label>
                        <div class="col-sm-9">
                            <input type="text" class="form-control" id="description" name="description">
                        </div>
                    </div> 
                    <div class="form-group">
                        <label for="amount" class="col-sm-3 control-label">Amount</label>
                        <div class="col-sm-9">
                            <input type="number" class="form-control" id="amount" name="amount">
                        </div>
                    </div>
                    <div class="form-group">
                        <label for="status" class="col-sm-3 control-label">Status</label>
                        <div class="col-sm-9">
                            <select class="form-control" id="status" name="status">
                                <option>Paid</option>
                                <option>Unpaid</option>
                            </select>
                        </div>
                    </div> 
                    <div class="form-group">
                        <label for="date" class="col-sm-3 control-label">Date</label>
                        <div class="col-sm-9">
                            <input type="date" class="form-control" id="date" name="date">
                        </div>
                    </div>   
        </div>
    </div>
</div>

Do you have any idea? thank you