I use one that is a telephone, text, email, RVM all inside a CRM with campaigns and scheduling.

And they have the sellers telephone numberAsk them 3 questionsIs the house currently listed with a real estate professional?

Mass Texting: This uses an ATDS (automated telephone dialing system).

However it does a lot...Here is a small list of things it doesTelephone Features: Call DialingLocal NumbersToll Free NumbersCall RecordingCall ForwardingCall NotificationsVoicemailVoicemail TranscriptionNumber LookupsCall QueuesCall TransferringHold MessagingRVMsProperty to Telephone Number Appending Text Features: SMS Send & ReceiveMMS Send & ReceiveVoice BlastsDrip SchedulingRecurring SchedulingSend Later SchedulingUnlimited Longcode KeywordsLong Code (Local Numbers)Text CampaignsEasy To Remember ShortcodeText NotificationsShort Code KeywordsEmail Features: Email CampaignsSimple Email CreatorsDrip SchedulingRecurring SchedulingBeautiful HTML CreatorProfessional Email TemplatesSend & ReceiveAttachment CapableFile LibraryCustom WebformsMultiple AgentsTag ApplicationsCRM Features: Complete CRM ManagerBuild Custom Contact FieldsComplete Communication ManagerCaller IntegrationText IntegrationEmail IntegrationOnline CalendarCampaign ManagerTag ManagerTask ManagerAutoresponderContact OwnershipChat Features: Live Chat IncludedAutomated Initial ResponseCustom Start ButtonEasily Collect Contact InformationInstall On Any WebsiteEmail NotificationsSMS NotificationsAutomated WorkflowsSimple Chat BuilderCommunication HistoryAutomated Contact CreationCustom BackgroundThis is a complete telephone, text, voice blast, email and CRM platform, all in one. 

PURCHASE AND SALES AGREEMENTDATED: ________________PARTIES: _____________________________________, as Seller, and ____________________________________, asBuyer, whose mailing address is _______________________________________ and telephone number is _______________________.

Secondly,IMHO, if you cannot answer your telephone 100 percent of the time during reasonable work hours then you need to go exclusively to a VM system or hire an Answering service.Doing so will give everyone the same advantage to sell you their home.Here is a voicemail that has worked great for me... 

Google their telephone number, interview the neighbors for their contact info and if they live local and its reasonable maybe knock on their door.

The great thing about utilizing skype is that you can also record your calls to sellers to listen back to and help grow your telephone skills.

Hi Ryan...Always a telephone number...

Find the prefix for an area you want to buy in and call all 10000 telephone numbers.