POA cancellation after made Sale deed and non receipt

All transaction in same one register office Power of attorney filed By Principal A to Agent B 16 SEPTEMBER 2005 Sale of Agreement made Agent B with Purchaser C 24 OCTOBER 2005 Sale consideration mutually agreed 15 lacs Paid 5 lacs by cash at the time of signing agreement it continue say in doc by following... "(and receipt of which sum the vendor doth hereby admit and acknowledge)" and also conditions say the proposed transaction is to be completed within period of 12 months And also say the vendor agreed to execute sale deed or deeds in favor of Purchaser C or his nominee/s on receipt of balance sale consideration. CANCELLATION OF POWER OF ATTORNEY 10 AUGUST 2010 by Principal A reason not communicating any details and payment of receipt to him more than 5 years by Agent B. Sale of agreement also cancelled 5 years 7 months after filled 4 May 2011 return amount 5 lacs by POA AGENT B to Purchaser C. Same day 4 MAY 2011 POA Agent B and Purchaser C and his 2 close relatives names Made 3 SALE DEED .Cancelled sub parting schedule in 3 parts made 1.Sale deed value 12 lacs 86 thousands Name of Purchsaser C 2. 4 lacs 80 thousand Name of purchaser C Wife 3. 8 lacs 21 thousands Purchaser C Son Total 25 lacs 87 thousands collected by Agent B after cancellation power and Sale agreement also. Agent B never give any receipt of amount to Principal A at the time of sale of agreement and also after sale deed also. The PRINCIPAL A filed a SETTLEMENT DEED in favour of His SON A+a. 09 JULY 2011 All the transactions filed in the same one Sub register Office (SRO) Chennai. QUESTIONS Who is the absolute Title owner at present ?. What the roll of SRO for this Happening? Principal A have PATTA and Possession can transfer the name to his Settlement deed son legally to revenue dept ? Settlement deed son A+a can sale the property to another party and the buyer . How can ? who can ?cancel the sale deed filed after Cancellation of Power Of Attorney by AGENT B. Who is the Culprit. If i would like to purchase the property what will the procedure? How can short the problem in A short period.