After paying for the full version I was unable to find many of the advertised features, such as the ability to write to a tag

Not impressed, £6 for something that doesn't work. How do I get a refund?

Doesn't work for me. No refund button so I applied for a refund within 5 MINUTES of purchase directly with Google Play only to be told 2 days later that it doesn't meet their policies for a refund from a no-reply email!