Need advice - Should I dig a new borewell or redrill the old one ?

Dear Sir/Madam,

We got a house constructed 1-1/2 year back on contract basis with submersible pump based borewell, the depth was 125 feet and water hit at 45-50 ft. The borewell worked well for 6-8 months but then after that during summer the water stopped i.e. after starting motor it works at full pressure for 5 mins then stops, then we wait 20-30 mins and restart this and again the same thing . The local borewell company said because its summer that's why water is less. Three months back the pump stopped working when we got it reparied and slit and sand particle were in it after that we flushed the borewell and reinstalled the pump, the pump height to bore well is 80 ft. Even after flushing the borewell gave mud water first 5 seconds then clear water 5 mins then the pressure went low for 3 mins then it completely stopped after 5 mins. We somehow managed with this and the mud water by allowing the mud to settle in the tank and use the filtered water transferred to secondary tank but then again now three days back the pump failed. When we got it out and took it to company they found the rotars that sucked the water were completely shattered and said the cause was sand and slit. We also measure the depth of the borewell and noticed it has decreased to 80 ft to where casing is done. We have now put the pump at 65-68 ft and getting same muddy water water so we stopped the pump now. The company is saying the depth is were shallow that is why all this problem, but when we asked to do a rebore and increase depth they say its not advisable as it would cause more problems later so it would be more better to dig another one with 250 ft depth rather than increasing the depth of this. What we want to know is that is it true that if we were to rebore the well from 80 ft to 300 ft it would cause problems because we don't have any place to drill another borewell as our house is a duplex constructed on 15 x 40 sq. feet, please advise whether is it really necessary to make new bore or we can reuse the old one by increasing the depth.

Eric s smith