The following sentences, which one is correct? Or any suggestions?
The Web800 service supports locking a calling number when the call times of the calling reach the upper limit in the specified time segment.
The Web800 service supports locking a calling number when the number of call times of the calling reaches the upper limit in the specified time segment.
Neither is correct. You have a very long, very complex sentence. This has resulted in many errors and confusion. Try to split the sentence up into shorter, simpler segments.
"... of the calling reach ..." and "... of the calling reaches ..." are both wrong because you need a noun in each e.g. "... of the calling [noun] reaches ..." Insert the noun of your choice.
"... the call times ..." Is this supposed to be a number of times or a length of time? To put another way, is the limit 6 calls or 6 minutes.