@Marvin Meng I use Buildium which allow me to accept payments online through the resident portal.

In Los Angeles, visit website www.hacla.org .....Landlords Tab.....Landlord Portal.

I loved the management by American Campus Housing (University Edge, U Pointe & the Union complexes) as a tenant since there was onsite management and an easy portal.

Oftentimes, PMs will utilize management software (if they don’t, keep looking) and provide the owner with access to the portal.

Do they message the realtor, or is it some portal in their site that messages are sent to?

Finally, they revoked my access from their portal, since I'm no longer their client, which doesn't allow me to look at further transactions.In short, they hijacked my funds and decided not to respond. 

We handled it with the tenant.On the Airbnb front, I made a written request to Airbnb's support portal for Airbnb remove the review for two reasons: (1) Airbnb's policy is that guests are supposed to tell Airbnb if there is a strong odor that makes it untenable; (2) guests are not to "refer to circumstances entirely out of the host's control."

Did they send you to a portal to submit your offer?

Then contact them through the portal and try and set up a call. 

Professional company with more rentals than all other managers combinedOnline marketing, tenant and animal screeningHigher rent rates because we know the market better, have a better reputationBest screening process money can buyProven, written, and enforced policiesFree evictions and up to a month of lost rent reimbursedI cover up to $5,000 in pet damagesI cover up to $2,500 in tenant damagesEvery Tenant carries $100,000 in renters insurance, guaranteedOnline portal for owners and tenantsThat's not the entire list.