Using Mobilink Wifi Device Bundle on Existing Huawei Device

Salam everyone, hope you can help me on the following:

I had purchased Huawei wifi device E5330bs-2 from UAE and have been using telenor data sim on it and it was working perfectly. Now mobilink/ Jazz have launched their 3G in my area so I wanted to switch to it (as it is loads faster than telenor). However my data sim is not giving regular 3G speed in the Huawei device and when I rang mobilink helpline and asked the guy that "why is the data sim not giving good speed since I am using same device as being offered by the network.", he told me that data sim can only work on the mobilink device.

I have also noticed that I have used around 370MB but only 15MB have reduced from the package amount (50GB). Can anyone please give a suggestion what can be the reason behind this. Is it simply because the package is not properly subscribed on mobilink's end? (Although the mobile portal is showing that bundle has been subscribed).