So...basically we were sending this email to Bolivia, Argentina and Peru Post to inquire on our items sent to them, we received no reply after multiple message. So we are thinking it could be they do not understand English well enough thus sending in Spanish might help... A million thanks in advance...
*Ps: If you need some short translation in Chinese, I will gladly help.

Dear Colleagues

Greetings from Singapore!

We would like to check with you if you have any issues with the enquiries we sent to you as there are numerous enquiries that have lapsed the 60 days period for investigation and we have yet to receive any conclusive replies from your side. Attached is the list of items for the past 6 months (Enquiry period from Oct 2016 – Mar 2017) with no conclusive replies.

On a side note, we would like to check on the feasibility of raising enquiries for Registered Articles through GCSS (*this is a system name) and would like to seek your kind opinion.

Looking forward to hearing from you soon.

Thank you.