Please be assured that your messages are being sent. Every time you contact a home owner or house sitter through our contact form system a copy of the message should be listed in your 'Sent' folder in your Message Centre.
Also, there is a feature that allows you to see if the person has read your message. You can do this by going to your Message Centre, sent folder and check the 'Read by' column in your email list. Please note that this feature was only released in May 2017, so it doesn't apply to any messages sent before then.