Cash or accrual - foreign income

Dear Friends

A Company earns foreign Income from Parties from countries like South Africa, Pakistan, Bangladesh etc

However, there is uncertainty of subsequent payments to be received from some parties in countries like Nigeria, Pakistan etc due to various reasons. 

My Questions are :

1. Can the Company recognize the payments from these parties on cash basis now? (earlier it was on accrual basis)

2. As the amounts are not Material in nature, will it violate AS-9 Revenue Recognition?

3. Also, please kindly also mention about any permission to be taken from RBI to write off amount of foreign parties in case the income is not received from them?

Any help in this matter is highly appreciated

Thanks & Regards