Facing Continuous Issues of On 7

Hi Dimers I am using Samsung Galaxy On 7 . As u know either we can put two Sims or 1 sim and 1 memory card . I have put 2 sims . U know the devices memory is 8 GB out of that almost 4 GB is available for use . In that I have applications of approx 1 GB . Now the problem is the device is getting struct approx every 10 mins of browsing and any type of usage and within some mins it gets automatically restarted . Or if it doesnt the only way to bring it back to function is remove battey . I m irritated of doing this again and again . I cant do a single thing properly beacuse of this . I contacted the customer care twice and they advised me to download Smart Tutor app and they will check the device . I did that . I agree that the team was quite helpful . They checked up my updates and storage and all is fine . They also advised me to maintain min space of 1.50 GB and I have done that too . Still the bugs arent getting solved . When I phone them , till some 30 mins the mobile is ok . And after that the same story continues . Can anyyone help me out . Is there any problem with my device ? I too havent downloaded any antivirus and battery savings app and the team too told NO when I asked wheter I should download this . Is anyone having On 7 and using 2 Sims facing the similar problem .