Data Sim Problem

Hello,
I have 2x 3g Data Sim, i Configure on my laptop to connect to other one on mikrotik 951 to request data through it.
when i setup it (PPP) it’s work fine but i have to chose no add default route, when i enable add default route it’s connect and disconnect every 1 sec.
i asked isp , they told me that i have to not use unicast. or prodcast
so what i have to do in this case ?i want to make the second data sim connect to the first one on mikrotik and forward to request that is coming from my computer through mikrotik.
thanks.

resolve by add a route pref soure ip = mikrotik data sim ip and dis = remote data sim ip