'sin-ter-ing vs. sin-'te-ring

American english vs. carabao English.
That is the gist of the story. Here goes, at the office, we had a teleconference with our British clients. I was the one who was asked by our group to speak to the client over the phone. I speak with an American accent (not Bisaya accent as what our company's boss thinks). Everything was OK, every little giggle was bearable for me. Then one time, I was to tell the word above (sintering) and lo! everyone is laughing, as if I just blurted out or made a joke. My "big mistake" was that I pronouced it like /'sint-ring/ (accent in the first syllable with the central "e" after t almost unpronounced). Then they say, "why did you pronounced it like the word 'centering'?" And I'm like, OK, I think I made a mistake right there because 'centering' is supposed to be pronounced /'sent-ring/. I gave in to my officemates demands, I pronounced it like /'seent-ring/ and /'seen-te-ring/, still, deafening laughs I heard. I'm quite lost by that time, I thought I made an incorrigible beyond the Universe mistake. You know or if you didn't know the "i" in American English is relaxed, unlike in French and Spanish where the 'i' is pronounced like 'ee' in beet. The 'i' is relaxed, like the 'i' in "pits". It's not pronounced /peets/ rather it's 'pits' almost the same as "peats".
With some of my officemates' ignorance, uncosmopolitan, and unprofessional behavior, I was red in the face literally. They told me that it must be sin-te'-ring, accent to the second syllable. Whoa! Here is another "deaf" Tagalog pronunciation of English words. For non-Tagalog readers, Tagalogs are noted for placing accents in the second or third syllable of English words. The norm in standard English is of course, the first syllable. A good example is the word 'temperature', in standard English it's pronounced /'temp-re-chur/ accent in the first syllable, Tagalogs almost always pronounce it like /tem-pe-'re-tsur/, accent in the third syllable, which is well... here's more, "circle" is pronounced /sir-kel/. Obviously Tagalogs are blind and deaf with the English schwa.
I'm really pissed off with these people. I love laughing and I like to be the hot seat for jokes but this time, their incompetent "way of saying things" seems like a Pandora's' box run berserk. The event was an official function people, it's OK with me joked among peers but with the client? I'm sorry I'm serious with those matters, and that time, I was not communicating with boisterous officemates but with the other end of the line in England. Their incompetence and judgmental behavior based on their ignorance and obvious unprofessionalism makes me sick.
Check your dictionary first before you laugh.