To catch or to contact in formal form?

Hello everybody,
Could you help me please about these sentences?

Hello Lara,

Hope you are well.

Before I left I tried to catch you in your office or on your mobile to say good bye.

OR

I passed by your office and also tried contacting you on your mobile to say good bye.

In English you can say "I passed by" (is in I went passed your office, peered in and you weren't there), "I dropped by", "I stopped by", "I tried to catch you at..." plus many many more... 

in the UK, we almost always say "mobile" rather than "mobile phone" even for formal situations.

To catch or to contact in formal form?

Hello everybody,
Could you help me please about these sentences?  Could you help me with these sentences please?

Hello Lara,
hope you are well. I hope you are well. 

Before my leaving I tried  Before I left I tried 

- to catch you (in your office,on your mobile (1) phone) to say good bye/for saying good bye
OR

-to pass in your office and contact you at mobile phone to say good bye/for saying good bye
A lot of warm regards to Helen and Jonh, also from Riccardo. -stop by your office / to contact you by mobile, to say good-bye.  Helen and John, send their warmest regards to you, as does Riccardo. 

Request: Can I use TO CATCH instead of TO PASS and TO CONTACT in the formal form? (2)
Is it correct this sentence? Is it correct in these sentences?

Thanks very much,
Best Regards,
Lara

Very well done!  

(1) In the US a 'mobile phone' is also called a 'cell phone', or a 'cell'. You can say "I'll call you on your cell." for casual speech.  For Formal speech "I will leave a message on your mobile phone", or "I will contact you on your mobile phone," are more appropriate.   

(2) In the US, "To catch you" is casual, "To contact you" is formal.  

"To pass by" is not used frequently here, "To stop by" is used, and is both Formal and Casual.