The final order of the Department of Revenue adopting the DOAH hearing officer’s recommended order is supported by substantial competent evidence and is not otherwise shown to be erroneous. Section 120.68, Florida Statutes (1978 Supp.). One transaction or the other was taxable under Chapter 212, Florida Statutes (1977): either that transaction by which appellant purchases pagers from its supplier, or that transaction by which appellant supplies pagers to its customers for use in its paging service. Which transaction is taxable depends on characteristics which appellant itself imparts to its dealings with supplier and customer. Appellant’s evidence and argument do not clearly characterize the transactions other than as perceived by the Department of Revenue. A case for estop-pel is not shown. The Department’s order is therefore

AFFIRMED.