If you are a foreign tourist let me attempt to explain the phone system.  First there are multiple phone companies and that translates to needing a sim card for each company plus knowing what prefix equals the number you are calling so you can select one of the two Sims in your cell phone or insert another.  Secondly phones are not used for calling.  98% of what a cell phone is used for here is texting or checking social media sites.  Third, you have to buy a "load" to be able to do anything with the phone and loads can carry malware.  I once got 32 texts within minutes of buying a load.  Who were they from?  A world of scammers, prostitutes and, of course the phone company itself (5).  On the other hand without a cell phone it is not possible to stay in touch with anyone.  Is there a solution that might make sense.  Possibly, assuming you have limited need to call the world and only a couple of numbers to call or txt.  Buy a cheap phone, put in the appropriate sim cards and add the two numbers to contact list.  Last note of interest.....txts get answered.  Phone calls far less so.