MTN IS A BIG *******,BE CAREFUL WHEN BUYING THE VOICEMINUTES

I bought R165 airtime this morning and i transfered thw R150 to All Network Voice which will give me 380 minutes and i made a call that lasted me for 1 hour 29 minutes,I did not finish that call when i heard that i have 1 minute remaining.Mtn is a *******!!!! i always buy 800 minutes for R250 and i always ask myself why does it finish so quickly atleast now i know that we are being ******😡😡😡😡😡😡😡