I have a client who has submitted work receipts relating to her income received through self employment yet the CRA has deemed it that she needs to submit deposit receipts that reflect the numbers received. Those deposit receipts are not there since the transaction was made in cash yet both parties are claiming on their 2020 taxes. Options were limited to bank statements when discussed with a CRA employee, the local MP was also contacted to simply relay the message from CRA with no more options presented besides the bank statements, which are none. What else can she do to proof a secondary form of the income received and employment had?
“since the transaction was made in cash”
For cash transactions, there would be signed (by the customer) cash receipts, would there not, to provide documentation sufficient to comply with Section 230’s mandatory requirements? That should do it! 
(Recall the heavy potential penalties for not complying with section 230, so clients should always be very strongly encouraged to comply).
You would think but even with a signed official receipt and a signed income received note that is specifically provided by CRA themselves, they are saying it isn’t sufficient enough. I’m assuming once the years taxes are filed that it possibly could be enough to receive the backpayments.
"signed official receipt and a signed income received note "
I don’t know what thiae are?
S230 requires tharlr your client keep business books and records as required by that section. Get your client to give you those records.
Caution your client that without properly maintaining those business books and records he/she could be prosecuted (even go to jail, theoretically, but cra never seems to go quite that far).