I've been using this module for some time now and had no issue.
But recently it started giving me an issue where is does not tune to a correct frequency.
I do my testing using a RSSI strong station (106.5Mhz), At times it tunes to 106.5 but I can here only the white noise. Now it only tunes to 189.30 and here no white noise. I tried another same module. Same result.
I know that, and I gave you a solution without having to use level shifters.
I2C is open collector/drain, and logic voltage depends on where you connect the pull up to.
If you disable internal pull up, there is no 5volt pull up on an Uno/ProMini.
Google something like "Arduino disable internal pull up".
This has of course nothing to do with your problem.
Did you try code from other sites.
Did the library come with examples.
So is this mean that if I'm to use pull-up resistors in both sides (3.3v and 5v sides) of the I2C line, I should only consider a level shifting and or else disable Atmel328p input pull-ups of I2C lines and use without pull-up resistors and level shifters?