Hello sir, I'm working wih A2Billiing for 7 years. Please check my recent project reviews here -> https://www.freelancer.com/u/ivan381eu.html
Also, I have a slight suggestion regarding point 2, I'd rather hide calls to DID from CDR displaying then delete it from database. Deletion records from CDR is nasty job so if anything goes wrong CDR will be screwed.
Also, I'll need detailed explanation for points 3. and 4. but I'm 100% sure I can complete it in time.
Best Regards,
Ivan Vujisic
Freelancer username: ivan381eu