It appears that the digitizer (touchscreen) connection has either come loose or the digitizer is faulty and has to be replaced.
Here’s a link to the ifixit iRulu AX760 Screen Display Replacement guide. It is useful as it shows in Step.6 and Step.7 the digitizer ribbon cable connection to the systemboard, so that you can check if it is OK.
If it appears to be OK then you’ll have to replace the digitizer.
They are not that expensive. Here’s a link to just one supplier.
It is not a recommendation to use them. It is shown to give an idea of the cost of the part. (I think that this is the correct part. Please double check your model number).
There are other suppliers online that may suit you better. Just search online for iRulu AX760 digitizer part to get results