Update existing C4C BuPa relations

Dear Experts,

I'm struggling with differences regarding contac person relationships between C4C and SMC. Due to a missing SDK development on behalf of the C4C tenant several account update messages (by deleting BUP001 relations in the C4C system) were not sent to SMC. I've already tried to re-send all the customer's BUP001 relations, the whole account and contact person objects affected (using Extract Data to External System in C4C) and data workbench update of the affected account to SMC. Unfortunately it seems not possible to trigger the synch of obsolete relationships from C4C to SMC in order to solve the relationships differences. I know the case is somehow complex but maybe some of you have experienced similar problems and can share an approach.

Thank you in advance.

Best regards,

Max