This is weird... Who on earth still uses SIM contacts? Even the rSAP spec says that you shouldn't query SIM contacts via rSAP.
Maybe your SIM card uses a strange way of storing the contacts. You may try to delete all SIM contacts (don't ask me how) or install the SIM phonebook plugin (
https://play.google.com/store/apps/deta ... bookplugin). This replaces the real SIM phonebook with an emulation.
I don't know how the SIM card can possibly influence email receiption. Either you have Internet or you don't. Maybe it is simply much slower for whatever reason?
I don't think the Audi plugin will fix your problem but you may try. You can't break anything.
Did you try what happens when you directly plug the same SIM card into the car?
rSAP is not very common in Audis and so far I have the impression that it is not working as well as with the VW Premium, which is by far the best rSAP box available. But I thought the recent headunits have the same base (MIB), so there shouldn't be a difference...?