Hello Mr. Farid.
I went to the National Thal. Conference in Lahore earlier this year where the person who manufactures the pumps locally was also present. Many people complained about the failure of the pumps. He then explained that the reason of him using the cheaper quality components were to make it affordable and he says that he replaces all the defective pumps that come to him free of cost. However, if you don't want to consistently send him back the pumps for repairs then he recommended to buy the expensive version of the pump which was about Rs. 11,000-12,000 (Could be more in the market).
So, you can go check in the market for the expensive version of the pump. I have forgot the name of the pumps but they were in the name of his daughter.