It sounds to me like a POTS telephone wiring error of some sort, that could likely fry your OBi if you can't diagnose it.
Do you have access to a voltmeter and / or a telephone line tester (a dongle with red and green LEDs)?
If so, then unplug the POTS/DSL line from the OBi. Either open up the RJ=11 wall jack, or use a RJ-11 cord that can be cut and the wires stripped for testing. With no equipment plugged into the the circuit, it should read about 48 volts, plus or minus a few volts. If a phone on that circuit is plugged in and off-hook, then the voltage should drop to around 12V. The only time it should ever read in the 70V-100VAC range would be if it is ringing. If it consistently reads above the 48VDC range with nothing connected other than a voltmeter, then contact your telephone company (Claro), as something's wrong. Plug a DSL filter into the wall jack. Plug your cordless phone into the DSL filter. Does it work normally (dial tone, places and receives calls, rings)?
RE: phone line relay, yes, the relay was removed from later versions as a cost-cutting measure.