Don’t worry about signal levels in your network. Just put more base stations in. If calls drop out, the customer will re-dial and the mobile vendor obtains another flag-fall.
Employ only so few customer-service operators that the customers will need to wait on hold for long periods and eventually give up trying to report any faults. This will also make your statistics look good in the eyes of your competitors and government regulators.
I hope that is of help.