Poor service

i took my Samsung S7 edge for repair the the Service centre at the Grove in Pretoria, that was on the 23rd August and it is now 1st September and still i have not got my phone and they keep on giving me the run around. I then today phoned various service centres around the Pretoria and Johannesburg to find out how long it would take to order and install the main board and was told by three different centres it would take no longer than three or four days to order the part and install it. I then mentioned the problem i am having with the Grove service centre and all the people i spoke too including a person at Samsung head office all said there are big problems at the Grove. The question i would like to pose is am i guaranteed to get my phone back, should i collect the phone and take it elsewhere to have repaired as it seem that there seem to be serious problems at the Grove?