Callista Cover is an optional, annually renewable service which ensures your system is always up-to-date via regular system upgrades, call pricing tables updates, PABX driver updates and on-line user guide updates.  This service also provides unlimited telephone support and on-line remote access support directly from our Help Desk and access to unlimited downloading of upgrades and updates from our website whenever you choose.  Callista Cover can be paid in one annual payment by cheque or credit card, or by Direct Debit in monthly instalments.  The monthly instalment option is available to New Zealand customers only.