Following are some steps you should adopt before calling to 1236 Support Service or lodging complain, if you face slow browsing on these devices.
Steps are as follow:
1. Check mode (should be EVDO)
2. Check signal strength (should be more than 2 signals)
3. If signals strength fine then
a. Please check torrent, proxy (should be disabled).
b. Check Antivirus (should be disabled).
c. Check speed from speedtest.ptcl.net and verify speed.
d. If getting <= 2 signals than
1) Check signal strength by changing location
Still not solved, then you could go for lodging complain or visiting nearest PTCL customer care centre.