Abdul Rasheed,
IP Office developer support is provided to support enabled and higher level members in the DevConnect Program through our ticketing system. Information about membership levels and the application process is available at this URL:
https://www.devconnectprogram.com/site/global/program_benefits/membership_overview/index.gsp#tabs-1
Since you mention that the application was developed by a third party (unclear if that is you or a different company), I would first start by contacting them and inquiring about support for their application, whether there are upgrades for it. You don't mention the third party product, or what release of IP Office you are on, nor what version of TAPI drivers you are using, nor if you have checked for updated TAPI drivers (make sure they are compatible with your IP Office version before attempting to use them).
My immediate guess is there is a memory leak somewhere, but as I indicated developer support requires a support enabled or higher level of membership.