Custom Module Value Lookup update

Custom Module Value Lookup update

Good day,

I have created several custom modules, and considering the limitations, my implementation is working OK. I do have one issue. If I have a lookup between modules, when I change a value on a custom module field, the change does not reflect don't reflect on the lookup. 
e.g. I have a module named "cloud services", which has two fields "service name", and "service price". then I have a lookup in the contact layout to bring in the service name and price the contact is using.

I need to be able to update the price in the contact layout once the price changes in the cloud service module.

Any help or ideas are welcome.
Thanks
Rudy