Share-a-load is not applicable for Postpaid line except for Load Tipid Plan holder since this is a treated as a regular prepaid account. Basically the load that was sent to you will not reflect on your billing, ask the sender to contact the Globe Hotline for further assistance. Regarding your inquiry if you can forward the load intended for the right receiver, no you can't since the load that was suppose to be sent to you will not apply to your current plan. Instead if you forward a load to the right receiver you will be charge for the said amount and this will be added on top of your plan.
Another share-a-load scam. If the text message saying you received a load is from a 4 digit number then it might be a valid one. Otherwise, if from 11 digit then chances are it is a scam. As stated above, postpaid can't received a regular load. So once you return the load then chances again are you will be charged 300 on top of your plan.