SESlingshot have been in touch - "When you order our service you are paying for a blog post link. Those blog posts are posted to the homepage so you actually get 2 links. As more posts are made to the sites those posts roll off and the extra homepage links goes away. This is what you are seeing as deleted. But, what you paid for it a blog post innerpage link"
The above explanation is perfectly acceptable, and I should have understood this in the first place. All I would say to newbies in my position would be to order one of these packages every single month - a one off post bundle won't do anything for you long term.
I will carry on using SESlingshot in the future - and understand that I will have to buy $400(ish) worth of links to keep progressing on the ranks each month.