LMAO! well this avatar is really me... if you feel concern... i'm sorry

I see some other potential problem in the above anyways.

From one of his previous post he says that
^SMGL: 1,"REC UNREAD","+27829554322",,"08/04/20,17:12:09+08"
could be the incoming string... so obviously, using his HSERIN line, it may return to the INT routine and spining around and around. my 2nd suggestion add a little timeout like this...
Code:
IntLoop:
    HSERIN 10, GETOUT,[WAIT("^SMGL:"),SKIP 1 ,str ID\28]
    HSEROUT ["CELL NO:",_
          ID[17],iD[18],ID[19],ID[20],ID[21],ID[22],_
          ID[23],ID[24],ID[25],ID[26],ID[27],10,13]
GETOUT:
@ INT_RETURN
this way + PBP type it should solve most, see all problems.

HTH