Due to regulatory changes in the UK ring tones market, ringtones billing systems can be very complex.

The most complex billing systems are recurring billing or subscription services. Considerations include:

• How does the customer un subscribe?
• How often is the customer billed?
• How are royalties calculated that a paid to musicians?
• What happens when a subscriber gets a link to a ring tone but never uses it?
• How is the use of the subscriber logged and is it legally done?
• Did the subscriber "opt out" of other related txt message marketing?
• What are the capabilities of the subscribers handset and how can this be deduced?  
• Use of MP3's, real tones, polyphonic and monophonic tones?
• How can delays in mobile phone networks delivering messages be taken into consideration?
• What is the best most valid way of deciding when a mobile number is dead or no longer in use?
• How can you work out if a subscriber is a pre pay or contract customer?
• What is the effect of the customer and the billing while roaming in different international locations?
• How can data be synchronised across multiple servers across different locations to ensure the appropriate level of redundancy and reliability?

A web based php application, with a mysql database can do all of the above and more and ensure that hourly backups of data can be done automatically between server locations so subscriber data is never lost.

When free mp3 ringtones are offered, the free ringtone must be delivered before the next subscription paid tones.  The use of a ping back system to confirm the free ring tone has been downloaded would ensure this is the case.